Biology Club

Migration test EXPLAINED - From visible stuff to atomic scale

noreply@blogger.com (Ahmed Ashraf) — Sat, 30 Mar 2024 21:39:00 +0000

Migration! You know when you are living in your hometown with your family whom you know the most than any other in the world and entrust them with all your heart, we are bonded tightly with them until we grow up and our passion grows with us and takes the wheel and then we begin to pursue it and migrate from our homeland. We sort of broke our bond and our connection with whom we grew up and chilled with.

This happens everywhere and to this day and to this current moment happening right now even on a molecular scale. Happening on a scale we cannot see visibly. But, we can feel it and experience its consequences.

This is what we call migration and this is what are discussing today but not on a huge macro-scale, we are referring to the small minute stuff where the fun exists

Definition

A phenomenon that happens when chemical compounds/elements move from their current matrix to the adjacent solution/food it is containing/holding/carrying/processing

Why do we say food matrix?

Food itself is a complex system consisting of various compounds existing altogether which gives it its physical, chemical, and organoleptic characteristics.

How does this phenomenon happen?

The movement of such compounds/elements falls under the definition of the law "Diffusion" which is the movement of molecules from a region of higher concentration to a region of lower concentration across concentration gradient till equilibrium is achieved.

https://byjus.com/biology/diffusion/

Food contact materials (FCMs)

Materials that come into contact with foods whether solid or liquid to contain/store/uptake/hold and to process them.

We have so many examples of these materials such as ceramics, rubber-based, plastic-based, aluminum, wooden, stainless steel, glass, and silicon-based

Food-safe material logo, this is an iconic symbol that implies that FCM is safe. It is applied before the FCM is yet to come into contact.

Observe the following pictures with the logo drawn on the label for the products

Now we get to the 3 big questions we need to ask ourselves and answer them through the lecture

What makes a good candidate for food packaging?
Origin of pollutants
How does a pollutant migrate to the food matrix?

Shall we begin the fun? (=

What makes a good candidate for food packaging?

What do you think?

· To begin with, it must be able to protect the food from the outside environment obviously

· Cost effective (why would I invest in something that's proven to be extremely expensive?)

· It shouldn't break easily or else I would be losing (Economical and reputational value)

· It can be recycled to some extent

· Have a long shelf-life (high durability)

· Easily handled, transported, and processed

All of these good properties are required when we are looking for a good candidate to protect our foods after all, we are doing this to ensure one major rule which is to provide safe and sound food.

Finding a material that checks all these properties is like finding the hero of packaging materials and of course, major production companies will definitely capitalize on that and produce an ocean size amount of it

Let's take one food contact material and dissect it to the smallest scale. PLASTIC! I think without a doubt we could say that over 90% of us have used or are right now in possession of a plastic-based food contact material.

Plastic has most of the properties we mentioned earlier so why not produce tons of it

It is as if we have found the perfect material, NO!, wrong!!! let's agree that nothing is perfect!

Image source
https://www.tradeindia.com/products/light-weight-smooth-finish-1-liter-plastic-bottle-8013853.html

Perfection makes a dead end, grayish life with no joy, once reached (if possible) then you have got nothing else to do.

So now that we have discovered one of the globally produced materials of all time, we are now bearing its consequences. These are the challenges we are facing right now, handling the material, its raw materials (resources) which is a finite aspect, and shifting to sustain the resources. Last but not least, disposing of it or the correct disposition process.

All that we are referring to right now are the contaminants, they are countless. Such contaminants can migrate from food packaging materials. We will be discussing one contaminant with all its aspects. And perhaps the famous one that can exist everywhere is "Lead"

Now that we have defined what a good candidate for food packaging materials is, we shift to the second question which is " the origin of pollutants/contaminants"

Let's look at where can Lead originate from

An everyday source we may not realize is traffic, a study was made on Forty-five traffic controllers of Alexandria, Egypt road intersections on the assessment of lead toxicity, and found out that the average blood lead level was 68.28 ug/dl while according to the Council of State and Territorial epidemiologists reference blood lead level value is 3.5 ug/dl - this revelation clarified the reasons behind some traffic controllers sudden death when they arrive home falling down on the ground breathless.

Image source - https://www.uags.com.au/symbolic-traffic-controller-600-x-600-corflute

Think about it for a second, you have people with god knows health conditions, their own workspace exists in a place where they are constantly experiencing non-stop origin of lead which is owed to the presence of something that is being the main reason for air pollution by lead.

This is because some gasoline use still has lead in it, (The use of leaded-gasoline) although some countries banned its use, some still use it. As well as, the products resulting from the lead-acid car battery.

Blood lead levels exceeding 25 ug/dl require immediate removal of the worker from the area to which blood lead levels increase

Image source - https://e360.yale.edu/features/tire-pollution-toxic-chemicals

Now we move on to a second origin for lead which is the plastic material itself and its additives. From here on we are digging deeper into the real stuff.

We need first to know how plastic is made/built. Think about it like how any building is built, you need bricks as the building units (main) you need something to connect each brick to one another (cement), you are going to need some supporting materials (things to provide overall strength) like iron bars and for extra rigidity, we will need sand and stones as fillers for any gaps and base reinforcement.

Let's put things into comparison, the bricks are the main units - the things that make up the buildings, the walls.

Same thing with plastic, imagine the plastic is the main building unit and I am using something equivalent to the bricks but on a smaller scale, we have main building units we call them monomers, and the connecting substance here is the bond that is making them attached to each other, and some added fillers and strength and rigidity providing additives to make the bottle withstand environmental factors e.g., UV light, oxidation, mechanical stress, and heat.

Monomers are like the bricks we discussed minutes ago when building, they are the soldiers, and they are the ones with the highest number in the system. Observe the following figure, a plastic bottle -these red dots are the monomers, they are the bricks we are talking about, these are millions upon billions of molecules bonded up together making up this shape we see right now.

Imagine it as if you see a pile of dust piled up together in a corner, if you just blow in it enough, this pile of dust will disperse into the air, and you will be able to see the particles of dust while they are still a little somewhat close to each other but then suddenly it is out of sight. Can you even see one particle? Of course not! so we can depict that the piled-up dust is a complete entity with atoms, these atoms are the dust particulates when they were piled up they were enough that we can see them.

The same applies to anything we see right now including us, we are piles upon piles of atoms connected to each other in a certain way in an unimaginable sophistication which ended up making the glorious wonder of you. You deserve to be appreciated. Keep going!

Besides that, we have ingredients that assist the building blocks with some properties that make it a good candidate for packaging a food commodity, such as:

Fillers, Colorants, Lubricants, Plasticizers, and Antioxidants all of them are joining the main raw materials that make up the plastic material

These materials are like stones, sand, and iron bars they provide rigidity, strength, and ability to withstand environmental factors such as heat, sunlight, humidity, air, and mechanical impacts

Some ingredients provide aesthetic value such as pigments that are used as colorants and make up any art on your everyday cup of coffee

For instance, we have different types of colorants they can be inorganic, organometallic or metallic compounds such as lead chromate which gives the color yellow, and Lead sulfate and molybdate both give a red color.

Furthermore, we have colorants that have cadmium as an ingredient such as Cadmium sulfide and Cadmium selenide giving yellow and red pigments respectively.

Image source - https://pubmed.ncbi.nlm.nih.gov/34030075/

Even though metallic-based colorants exist, some countries prohibit their use.

Colorants are another source of lead pollution in food packaging materials.

Now we visit another source of Lead which comes from the early stages of production, let's roll back a little bit to when we spoke about how buildings are built from building blocks/units. We related that to the plastic materials being made up of units that we called Monomers, a Greek word that is divided into two words "Mono" which is equivalent to = one, and "Meros" which is equivalent to = part, putting them together makes up the word "one part" so we have one part connected to another part and so on and so forth till we make up the building or in our case the plastic bottle we use every day.

These monomers or building units are basically one molecule/compound/part beside another, and another, and so on.. Millions upon billions of molecules connected together by bonds which are like the cement that connects bricks together, kind of look like this (animation of the monomers connected to each other making up the plastic bottle - Followed up by a zoom-in picture of what one single molecule look like)

The following figure is more of a microscopic 2d-diagram of what one particle of our main building units (monomer) looks like, the following circular shapes are molecules with the bonds connecting them.

Image source - https://www.sciencedirect.com/topics/earth-and-planetary-sciences/polyethylene-terephthalate

Polyethylene terephthalate or PET, is your everyday plastic. As a matter of fact, if any of you have a plastic water bottle right now, I would like you to look at the bottom of it, you should find this symbol on it (a picture of PET plastic bottle symbol).

Image source - https://www.vectorstock.com/royalty-free-vector/set-of-plastic-recycling-symbols-vector-23551758

This symbol indicates the type of plastic to which this bottle is made and there are several types of compounds that make up different types of plastics that have different uses, this is the exact building unit in its molecular form, consisting of ten carbon atoms, eight hydrogen atoms, and four oxygens

It's the compound that makes up the whole bottle, we consider one part or one molecule of polyethylene terephthalate as our monomer, our one part, our building unit. This is just one single compound/part. But, have one beside another and so on, we make what in chemistry is called a "polymer" which is a series of more than two molecules bonded to each other making up a long chain of bonded compounds together that make up our plastic bottle at last.

Image source - https://www.alamy.com/polyethylene-terephthalate-or-pet-pete-polyester-thermoplastic-polymer-molecule-with-plastic-bottle-structural-chemical-formula-vector-illustratio-image260834432.html

And this is another form of what it looks like (a picture of a series of PET molecules attached to each other)

Image source - https://www.sciencedirect.com/topics/earth-and-planetary-sciences/polyethylene-terephthalate

This is a detailed picture of what Polyethylene terephthalate looks like, it consists of two main compounds, an Ethylene group, and a terephthalate group. Now let's get to know how we even obtain these molecules which further elaborate on how Lead can ultimately exist in a matrix of compounds that don't have lead element as a contributing member of its compound structure.

Image source - https://byjus.com/chemistry/polyethylene-terephthalate/

Crude oil! The beginning of everything, Petroleum. A mixture of compounds that can make anyone rich once they find out that they have been seating before a gold mine! But why is that? well crude oil produces numerous substances that are used in different industrial aspects. Let's take a look, we have a variety of compounds with each one of them produces different products. Our main concern lies in

"Naptha series", Here lies a couple of compounds that make up different products with two of them being the raw materials for PET plastic production which are Ethylene and terephthalic acid.

Made by me

To obtain these compounds, a complex process must be done to the crude oil to extract and separate these compounds from the mixture that makes up the crude oil, this process is called "Fractional distillation" This complex step-by-step process is used to separate the mixture of compounds found in crude oil through heat at which one or more fractions of the mixture will vaporize with the most volatile compounds gets separated at the highest chambers with the lowest boiling points and the solid high boiling point compounds at the bottom to which the highest temperature exist and where usually the heavy metals can be found in abundance. While this process is the most common form of separation technology. Yet, it requires immense accurate implementation to avoid any impurities that can be separated into categories that they aren't supposed to be found in. This is due to the application of the temperature and it needs to be gradually done without the need of conducting it too fast since some of these compounds have close boiling temperatures so you may have impurities in areas that aren't supposed to have them.

Image source -https://www.alamy.com/diagram-showing-fractional-distillation-crude-oil-image444606928.html?imageid=4E336B6A-2317-45D0-A1A0-00B3330A2110&p=540308&pn=1&searchId=4e5272b96c5da6732d92752d6afca851&searchtype=0

This implies that there is a chance for sure that there is a chance of having heavy metals in any of the different categories of the distillation products and that's why we end up finding heavy metals like lead or cadmium in the raw materials.

As you can see in this table, the concentration of some heavy metals in a sample of crude oil, heavy metals concentrations (in mg/liters) are through the roof.

Image source - https://www.researchgate.net/publication/321148024_Alterations_in_the_Bio-membrane_of_Libyodrilus_violaceus_following_Exposure_to_Crude_Oil_and_Its_Fractions/figures?lo=1

Now that we have answered the second question, we move on to the third and last question of our topic which is "How does a pollutant migrate to the food matrix?"

No matter what we do, there is always migration. But, we always thrive to make sure it is incredibly in the safest levels and are at levels below the safe daily intake or detection.

LEAD!, It is obvious now that there is no way we could avoid it. It is now existing in our polymer. If we look at our plastic bottle right here and zoom in on a portion of it, this should be how the polymer looks like, the green-arranged alternating line is our polymer consisting of millions upon billions of molecules of polyethylene terephthalate molecules connected to each other side by side with some components attached around like any additives (e.g., plasticizers, antioxidants), as well as colorants (Recall: Lead chromate for instance), and of course, there exist impurities hanging around!.., Hanging like any disease that visit you and hang out with you sometime and leave.

Notice closely how uniform this portion and the arrangement of molecules are, this way of arrangement isn't just for show and tell, it exists and for a reason, it characterizes the molecules forming this arrangement it gives it properties. For instance, with such a pattern, the structure gets to be tough, rigid, and to an extent able to withstand heat.

Image source - https://www.sciencedirect.com/science/article/abs/pii/S0278691521004063

These types of patterns we call them "Crystalline patterns" You know the word crystal is implied on things and context that appear clear and understood well just like diamonds and how beautiful and clear they are! They are the perfect example to describe crystalline structures, the structures that have a clear uniform, and edged points.

Image source - https://www.astteria.com/blog/how-to-identify-a-raw-diamond/

This is a comparative diagram showing crystalline structures and their opposite "amorphous structures" and we know how strong diamonds are! they cut things, man! so this implies a lot about how just a pattern of atoms contributes to the physical properties of something.

Image source - https://www.geeksforgeeks.org/difference-between-crystalline-and-amorphous-solids/

On the other hand, we see amorphous structures and look at how unarranged the molecules are, this tells us a lot about what physical properties we are expecting. Moreover, heat stability as well is also shown to be stronger in crystalline structures than in amorphous types

Some materials can have both phases or structures in it, and we call them "Semi-crystalline" and our PET bottles fall somewhere in this category. It has some regions with molecules arranged, parallel to one another and uniform. On the other hand, some regions are irregular in arrangement.

These types of regions affect the material a lot and make it a good candidate to be easily released when affected by different factors such as heat, pH, contact time, and the existing solvent.

Now, we have seen what is like to be a plastic PET bottle with its building units' structure, here again, we have our building units colored in red and let's say these bright blue small circles are the lead impurities that exist in our plastic complex structure. By cutting off a piece from this bottle and examining it clearly on a smaller scale and zooming extremely close. We can see how something like this bottle behaves on a small scale. Remember that we are now dealing with things that can have diameters on a micro-scale.

We have an intricate matrix of molecules connected to each other with two main regions made up by our polymer, look at the arrangement, parallelism, and uniformity of crystalline regions, and tell me how something like that gets to be bothered easily! This is pure support in its form! molecules standing next to each other and in front of one another to protect and serve in every possible way while in contrast, the amorphous regions and their chaotic arrangement, what do you expect from selfishness!

These parts are usually the ones prone to migration much faster and their properties make them an easy target for temperature, the distribution of heat in this part is more devastating than the regular uniform regions and so the freedom of parts, molecules, or even portions is much much faster and easier in here.

Red dots represent monomers - blue neon dots represent lead
Image source - https://www.sciencedirect.com/topics/earth-and-planetary-sciences/crystallinity

To fully understand what temperature could do to anything, we need to look at the basic phases of life (Solid, liquid, and gas phases) they are the three phases of matter.

Solid state matter is expressed when the molecules are extremely close to each other, with strong bonds attached to every molecule intact/very close and once let's say the temperature is applied to it, the integrity of the object begins to stretch and this on a molecular scale is due to the increased kinetic energy resulted from an external source which is heat, energy was gained due to it and so the electrons were excited and this gained kinetic energy resulted in increased mobility of the molecules and so the bonds stretched and the solid state morphology began to disintegrate and change its strong form to liquid state which is expressed as molecules with bonds less close to each other than it was in its solid state.

By continuing to apply heat to the matter, bonds no longer strongly tact anymore and even stretch much longer creating a state where atoms are a part of each other and thus enter the gas phase.

Made by me

When the temperature rises let's say from a hot drink, the heat is distributed everywhere in the system even the contact material, and taking into account many factors such as the history of this plastic starting from how it was manufactured, quality of raw materials and where the additives/substances added to aid the polymer production and give characteristics to the final product, in the right concentrations and according to regulations.

All of these points account for the percentage of migration whether it will be high or low or somewhat in the middle.

The increased heat with no doubt can affect and will make changes to the materials on the molecular scale leading to bond breaking and thus migration!

Made by me

Let's get into the real fuzzy yet amazing stuff. Here we have two atoms colored blue bonded to each other, this line indicates the presence of a bond, this 2D-imaging of how a chemical bond exists, and of course it is hypothetical.

It is more like an attraction force, remember that electrons are negatively charged and the nucleus of any atom is positively charged owing to the presence of protons which are positively charged particles inside the nucleus, and so, the electrons of one atom are attracted to the positively charged nucleus and the same with the opposite atoms' electron. Yet, they will never fully reach the opposite nucleus, Why?

Because of the repulsive force resulting from the negatively charged electrons from both atoms when they are approaching the nucleus of the other, these constant forces balance the bonded molecules together.

Atoms at any given system and state of life whether solid, liquid, or gas are constantly moving in their place. Observe the following figure, shared electrons between covalently bonded atoms are moving one at a time around each atom.

Let's apply temperature! >:)

Made by me

I want you to watch closely the behavior of the electrons, we are gradually increasing temperature, this increases the vibrational motion of the molecules owing to the movement of electrons, they are becoming more and more erratic.

Made by me

This vigorous action going on right now due to the applied temperature at a certain point will be overwhelmed by the increased input of energy (temperature) to a point that it will surpass the force that is keeping the atoms bonded together and then you have it!

You successfully separated a molecule!

Remember, this could be anything, it can be a monomer, a dimer, an additive such as colorants or thermal stabilizers, or it could be Lead!

Made by me

At last, the impurity existing in the weakly structured, and existing somewhere in amorphous regions will have a chance of leaving its boundaries, gaining some energy, and reacting with nearby neighboring molecules, or eventually migrate to the contained food matrix with its various competitive mixture of compounds and contaminate our food. Hence, Migration achieved.

Made by me - image source -https://www.sciencedirect.com/topics/earth-and-planetary-sciences/crystallinity

Link to the lecture fully in a video (ARABIC VERSION) - ENGLISH SOON - https://youtu.be/7az6rPBcr4o

Contact me at - https://www.linkedin.com/in/ahmed-ashraf-9157a0113/

References

Egyptian National Food Safety Authority Food Contact Materials Decree 17/2022
https://www.efsa.europa.eu/en/efsajournal/pub/5194
Noorlander, et.al., 2011. Levels of per-fluorinated compounds in food and dietary intake of PFOS and PFOA in the Netherlands. Journal of agricultural and food chemistry
Migration of Substances from Food Packaging Materials to Foods IOANNIS S. ARVANITOYANNIS &LOULOUDA BOSNEA
Migrating Levels of Toxic Heavy Metals in Locally Made Food Packaging Containers, Saimah khan, Abdul Rahman Khan
https://www.news.iastate.edu/news/2015/08/21/vorstplastics
https://www.fda.gov/food/environmental-contaminants-food/lead-food-foodwaresanddietarysupplements#:~:text=For%20lead%2C%20this%20level%20is,that%20ca%20leach%20from%20pipes.
Leaching of Lead, Chromium and Copper into Drinks Placed in Plastic Cups at Different Conditions, Oliver Ahimbisibwe et.al.
https://www.cdc.gov/nceh/lead/prevention/sources/water.htm#:~:text=Lead%20can%20enter%20drinking%20water,acidity%20or%20low%20mineral%20content
https://www.digicomply.com/restricted-substances/lead-molybdate
https://www.e-education.psu.edu/fsc432/content/overview-refinery-products-and-processes
https://www.bpf.co.uk/plastipedia/how-is-plastic-made.aspx
https://plasticseurope.org/media/plastics-europe-launches-the-plastics-the-fast-facts-2023/
https://www.e-education.psu.edu/fsc432/content/metals-content-and-total-acid-number#:~:text=Most%20common%20metals%20that%20are,the%20source%20of%20crude%20oil.
https://alevelchemistry.co.uk/notes/fractional-distillation-of-crude-oil/#Napthalene_series
https://www.eurekalert.org/multimedia/698438
Thermomorphological study of the terahertz lattice modes in polyvinylidene fluoride and high-density polyethylene Steffan et. Al
Microplastic Pollutants, Christopher Blair Crawford & Brian Quinn 2017 Elsevier
Assessment of Lead Toxicity in Traffic Controllers of Alexandria, Egypt, Road Intersections, Ahmed et. Al
Physical Metallurgy, Robert W. Cahn and Peter Haasen – Fourth, Revised and Enhanced Edition 1996
https://www.cdc.gov/niosh/topics/lead/referencebloodlevelsforadults.html#:~:text=The%20Council%20of%20State%20and,value%20is%203.5%20%C2%B5g%2FdL.
Alterations in the Bio-membrane of Libyodrilus violaceus following Exposure to Crude Oil and Its Fractions

Cells & Oxidative stress

noreply@blogger.com (Ahmed Ashraf) — Wed, 07 Feb 2018 23:53:00 +0000

Cells & Oxidative Stress

A tale of degeneration

The effect of free radicals on animal cells

A cell is a living being, a machine made up of millions upon millions of proteins though it has no ability to express feelings, Yet it still considered to be an individual in our body. Despite that, We have trillions of cells that exceed the number of stars in a milky way!

Effect of heavy metals - click on the image to see the big picture

Our cells are attacked daily by many foreign objects even if they were not to be seen or touched like U.V light, X rays, or any type of electromagnetic waves, Cosmic rays, heavy metals (e.g., Copper, Iron, Lead, Mercury), free radicals (Reactive oxygen species or ROS) and much more..., Still! God has given our body a great immune system and repair mechanisms that can make up any damaged parts back like.

Electromagnetic waves from weakest to the strongest

All biological polymers ( long-chain molecules formed of repeating units such as starch (glucose), proteins and nucleic acids) are subject to damage from the body's own heat and from the aqueous environment inside the cell, and DNA is no exception. It was estimated that 5000 purine bases (A) and (G) are lost each day from the DNA of each human cell because heat breaks the bonds linking them to deoxyribose. Therefore, any damage to our DNA that remains stable may or may not lead to the production of infecting-causing proteins.

One of the recent and up-to-date issues the world is facing right now that is the causal-agent of many degenerative diseases are the presence of Free radicals in our body or Reactive oxygen species as a synonym.

Free radicals are compounds resulted from a homogenous cleavage meaning that the products of the reaction have an equally distributed electrons. (refer to the following example explaining free radicals formation)

Source: https://archives.library.illinois.edu/erec/University%20Archives/1505050/Organic/Alkanes/AlkaneText/sec1-18/1-18.htm

Mode of action of Free Radicals (Oxidants)

Free radicals target mainly the cell's DNA or main proteins so that's why we are giving free radicals a number one priority and attention. They work on reacting with the DNA content disrupting it, leading to mutation and damage eventually to the production of unknown function proteins that could be lethal to our body OR it can induce cancer, degenerative disease which is yet none knows their exact origin, free radicals could be the reason for that besides other factors.

Having the cell's main proteins disrupted will alter the cell's metabolism, delaying its function and growth ultimately death.

This is what we call a state of Oxidative Stress to the cell, where it becomes prone to become cancerous, become harmful to the human body, or be the reason of a disorder considering the tissue it falls in.

Factors inducing the production of free radicals:

Environmental

Stress
Radiation
Exercise (heavy exercising)
Smoke ( even passive smoking )
Pollution

Inside the human body

Mitochondria

Stress, most of us get stressed out from time to time but that is a normal thing in our daily lives, But chronic stress like people who continuously having arguments or overly working can affect the brain size, structure and function right down to your DNA.

Stress begins with something called the Hypothalamus Pituitary Adrenal axis (HPAA), a series of interactions between endocrine glands on the brain (pituitary gland) and the kidney (adrenaline glands) when your brain face a stressful situation, this axis is activated and secretes a hormone called cortisol which ready you for taking an action. However, high levels of cortisol in chronic stress situations is dangerous; because it increases the number and activity level of neuro-connections in the Amygdala ( a part of the brain responsible for/control fear) which leads to a deterioration in the electrical signals present in the Hippocampus ( a part of the brain that controls learning, short memory and stress control) negatively affecting the activity of the HPA axis weakening it making it hard to control stress.

Eventually, your brain starts to shrink losing many synaptic connections altering the brain's cells and neurons which can lead to even more serious disorders like Alzheimer's or Depression.

Smoking and pollution are related to each other in the fact of cigarette's composition it has heavy metals in it like cadmium and lead, carbon mono-oxide that comes from incomplete combustions in some vehicle's exhaust polluting the air and thereby affecting our lungs and the cells inside which can lead to oxidative stress.

The waste products of mitochondria after carrying out metabolism leads to the production of free radicals ( it is not really that worrying) since our cells have its own defense systems But in our case here we are talking about a worst case scenario like having an individual who isn't taking care of his health and unfortunately the environment around him isn't clean, therefore the accumulation or the continuous production of these free radicals from the mitochondria exceeding the rate of the cells defense system will lead to mutations and serious damage.

How can our cells defend itself?

Our cells have few defense mechanism systems that use it to protect itself from free radicals, some of which are made inside the cell and the only one which is needed to be supplied by the diet we eat:

GSH = Glutathione
SD = Superoxide Dismutase
CA = Catalase
AN = Antioxidants (Food)

Catalase is an enzyme secreted by our cells which catalyzes the breakdown of hydrogen peroxide (free radical) to water and oxygen.
Check out the following link about the qualitative determination of catalase - https://allaboutbiologyworld.blogspot.com/2017/07/detection-of-catalase-in-potatoes.html

Superoxide Dismutase is an important antioxidant defense in nearly all living cells exposed to oxygen, it protects cells from damage induced by free radicals and has powerful anti-inflammatory activity.

It protects us from lethal free radicals like the fearsome superoxide a very active free radical, in a redox. the reaction it converts it to hydrogen peroxide which is the later converted to oxygen and water by Catalase enzyme.

On the other hand, our own phagocytic cells have the ability to secrete superoxide anion in combat against bacterial cells which is a very great methodology our body can do to fight hazards indicating that not every bad thing is bad.

Antioxidants

Antioxidants are more likely to be life guardians just like probiotics, antioxidants work on preventing any further damage to a cell by any oxidants (free radicals in our case), they can be natural or synthetic. Furthermore, antioxidants exhibit synergism, being more potent as mixtures than when used individually.

Natural antioxidants: polyphenols, carotenes, Tocopherols ( alpha, beta, gamma, and delta) and Tocotrienols (alpha, beta, gamma, and delta)

Artifical antioxidants: Butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), pyrogallol and tertiary butyl hydroxyquinone (TBHQ)

Antioxidants can be acquired from your diet means that you need to start putting colored fruits and vegetables in your diets such as Tomatoes, colored pepper, berries ( especially blueberries), honey, tea, strawberries, and wine.

Antioxidants work on by blocking the free radicals coming out from the environment or from the result of mitochondria waste-products so they are essential to every individual's body and are to be taken into consideration when you are preparing your meal or having a snack.

Glutathione

Is an amazing antioxidant that can bind to free radicals, heavy metals and any toxic compounds like cyanides due to the presence of sulfur-containing compounds ( it is composed of glutamic, cysteine and glycine amino acids) sulphur element distinct the compound in its ability to stick to many compounds that is why it is very important in our body and luckily our body can synthesize it ( there are supplements you can buy as well)

Acknowledgements

Check out the following animation on power point presentation by Doctor Dalal Askar, supervised by Professor Mohamed Mahmoud Youssef ( Food science and technology professor ) in Faculty of Agriculture, Alexandria University, Egypt.

Link - https://drive.google.com/file/d/18l0aOs6GkQEikzYGc-3ryb4vcVWmsZ4L/view

I do not own it, copyrights go to its maker - it was only used for explanatory purposes

References

https://www.nature.com/articles/ncomms16087
https://www.youtube.com/watch?v=Eh2PYQBICWs
https://archives.library.illinois.edu/erec/University%20Archives/1505050/Organic/Alkanes/AlkaneText/sec1-18/1-18.htm
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1876613/
https://www.youtube.com/watch?v=KLrzfwCY3uY
Pennington Nutrition Series Healthier lives through education in nutrition and preventive medicine 2009 No. 1
Food Chemistry 15306
https://www.youtube.com/watch?v=WuyPuH9ojCE
https://www.youtube.com/watch?v=zrwhSkeZceg&t=563s

Thyroid gland #Part2 Hormones Physiology & Hyperthyroidism

noreply@blogger.com (Ahmed Ashraf) — Mon, 29 Jan 2018 20:35:00 +0000

Thyroid gland

Part 2

Physiology and Grave's disease (hyperthyroidism)

How does the thyroid gland synthesizes the thyroid hormones?

The hypothalamic pituitary thyroid axis

First of all, the thyroid gland hormones are T3 (Triiodothyronine), T4 (Thyroxine), and Calcitonin, iodine is an essential element for the synthesis of these hormones, the thyroid gland is situated in front of the trachea below the hyoid bone ( the only floating bone), Moreover, the thyroid gland is very crucial to our body's metabolism at which it tends to make sure that the cells in your body are working properly by instructing every cell in the body when to consume oxygen and nutrients making it responsible for our growth and providence of better health, Furthermore, the calcitonin secreted by the thyroid gland, is an essential hormone that reduces your body's calcium level in the blood when it goes haywire, Ultimately, the thyroid gland allows our cells to use energy, grow and reproduce.

It begins when a part of the brain called hypothalamus secretes TRH (thyrotropin-releasing hormone) stimulates the pituitary gland to release TSH (thyroid stimulating hormone) which induces the thyroid gland to release its hormones, usually there is a negative feedback when the thyroid hormones are too much in the blood that should eventually inhibit the release of TRH from hypothalamus.

Now, the thyroid gland consists of lobules that each containing smaller cells called follicles ( follicular cells ) the lumen of these surrounded follicular cells are called colloid. Deep into a cellular level We have the cell membrane of the follicular cells which is surrounded by blood vessels that feed it with oxygen and the needed nutrients, the TSH molecules coming from the pituitary gland through the bloodstream binds to G-protein coupled receptors (GPCRs) present on the cells' membranes which then exchanges GTP to GDP thereby increases the cellular cyclicAMP (adenosine monophosphate) levels essentially increases the production of thyroid hormones ( T3 & T4) that eventually maintains the body's metabolism.

GPCRs are family of receptors that are found almost in every eukaryotic cell and has various bodily functions in our physiology. ***There will be a specific topic about GPCRs since they have a very important bodily function also it is a heavily researched topic***
But for now, you can understand their mechanism through here --> https://www.youtube.com/watch?v=ZBSo_GFN3qI&t=183s

How does that happen? The Physiology of Thyroid's hormones

A quick recap of the previous paragraphs, On a cellular level We have the thyroid gland's follicular cells forming the colloid surrounded by blood vessels which contain all the nutrients and essential elements required for the synthesis of the thyroid's hormones, it contains various cations and anions such as Na⁺, K⁺, Ca⁺², Cl^-, (HCO3)^- and I^- among other things.

Inside the follicular cells, the endoplasmic reticulum through which proteins are synthesized, Special proteins are synthesized inside which makes up most of the thyroid gland's proteins '' Thyroglobulin'' dimeric protein, It then travels to the Golgi apparatus to be packaged, After that it is transported to the colloid.

The follicular cells contain the following NIS '' Sodium and Iodine symporter'' (transporter), sodium and potassium pump and transporter called ''Pendrin''.

The NIS '' Sodium and Iodine symporter'', it allows iodine and sodium ions to go inside the follicular cells from the blood vessels at the same time, simultaneously the sodium can go out when the potassium ions come in; because the thyroid hormones synthesis occurs in the colloid and not in the follicular cells so the Iodide ions need to be transported to the colloid.

Pendrin ''transporter'' it transports the iodide ions to the colloid from the cells which is exchanged by chloride ions at the same time. Moreover, there are Peroxidases that oxidizes the iodide ions to iodine which is, later on, attaches to the Thyroglobulin ( several chains of Tyrosine molecules)

When one iodine molecule attach to thyroglobulin, We have MonoIodoTyrosine

Two iodine molecule attach to thyroglobulin, We have DiIodoTyrosine

If MonoIodoTyrosine (MIT) binds with DiIodoTyrosine (DIT) by ester bonds, we have triiodothyronine. But, If DiIodoTyrosine (DIT) binds with DiIodoTyrosine (DIT), we have Thyroxine, Yet the hormones aren't ready yet since the complex is still a part of the thyroglobulin.

The synthesized complex before will move back to the follicular cells in vesicles via pinocytosis, in which it will be attached to the lysosomes found in the follicular cells, they will bind to the endosome and break down the 2 hormones from the thyroglobulin to be released in the blood.

(Note: They also can be de-ionized into Iodide molecules and Tyrosine)

Inside the bloodstream, there are thyroid-binding proteins which act as emulsifiers to bind the thyroid hormones ( which are lipid-structures ) that are water-insoluble will bind with the thyroid-binding proteins to be delivered to the certain cells for metabolism regulation.

Let's take skeletal muscle cells as an example. The cells' membranes composition is lipid-bi-layered so the thyroid hormones goes easily through it, they enter the nucleus and bind to thyroid hormone receptors and retinoid X receptors, this will initiate gene transcription for specific mRNAs that will promote the thyroid hormone response resulting in the release of mRNA to the cytoplasm to be translate as a promotion for the thyroid hormone response ( this is like the feedback of the reception of thyroid hormones to the cells) and Ultimately, increasing the metabolic rate depending on which the area these hormones were attached to.

(Note: T3 is more active than T4, therefore when these hormones reach their destined cells, T4 is converted to T3)

The thyroid gland has a great impact on us regulating and maintaining our metabolism every bit of second, it promotes the growth of tissues, regulate your heart pumps, maintaining blood pressure, body temperature, triggers the production of digestive juices, and basically the thyroid gland's hormones are mainly concerned with the main thing that a human body cannot do without it which is our Homeostasis.

So what would happen if a defect occurred within the thyroid gland that made it secrete its hormones continuously with no inhibition of secretion....

A condition known as Hyperthyroidism is achieved (Note, Hyper=over) it is an over secretion of the thyroid's hormones T3 & T4, and there are a lot of causing agents that lead to Hyperthyroidism, certain medicine, auto-immune (Graves) disease, pituitary adenoma (Tumors), multinodular goitre, and thyroid adenomas especially the toxic ones ( and by toxic ones I mean the over secretion)

So let's pick up Graves disease as a causing agent for Hyperthyroidism...
Basically, Graves disease is an auto-immune disease, and auto-immune disease is due to the attack of the body's own antibodies to specific tissue in the body counting it as a foreign invader, and in Graves disease, there are auto-antibodies that attack the Thyroid's TSH receptors mimicking the function of TSH molecules (common one) by binding to the thyroid's TSH receptors, so whenever too much secretion of thyroid hormones, a negative feedback will happen in order to inhibit the secretion of TRH & TSH to stop the secretion of T3 & T4 but since these auto-antibodies already bound to the TSH receptors of the thyroid gland follicular cells, a non-stop secretion of the thyroid's hormones will be flowing causing an overactivity in the body ''Hyperthyroidism''

(There are Thyroglobulin antibodies & Thyroid peroxidase antibodies. But these are less common)

From where do these antibodies come from?

To begin with..., antigen-presenting cells like Dendritic cells during infections, they might present antigens of the thyroid's follicular cells marking them as an enemy to naive T-lymphocytes which when activated they activate a specific type of cells called B-lymphocytes which are transformed to Plasma cells ( a type of immune system cells that secrete antibodies) which will then secrete these auto-antibodies that will attack the Thyroid's TSH receptors mimicking the function of TSH molecules.

A microscopical view of the thyroid gland can show us packed follicular cells with a tightened colloid, and also traces of scattered T-lymphocytes.

Symptoms of Graves disease

Goitre, an enlargement of the thyroid gland, this can be noticed on the neck as a belly like protrusion.

Increased metabolic rate, therefore hyperactivity and irritability.
Difficulty in sleeping (Insomnia)
Sweating
Heat intolerance
Graves ophthalmopathy, since the TSH receptors can be found all over our body cells, sometimes the auto-antibodies manage to bind to the TSH receptors on the tissues surrounding the eye.
Weight loss
Graves dermopathy

Faster heartbeat (Tachycardia) which can lead to congestive heart failure (CHF)
Anxiety
Hyperreflexia - briefly is the overreaction of the involuntary nervous system to any external stimuli.
Hand tremors, an uncontrolled rhythm movement of the hand due to abnormal signals in the brain that miscommunicates with the hands and muscles - hand tremors can also happen due to neurological disorders such as dopamine deficiency like in Parkinson's disease ( you can check out this video ( I do not own it) about Tremor disorders: https://www.youtube.com/watch?v=-Y3kex_8UoY)

References

https://www.youtube.com/user/armandohasudungan
https://www.youtube.com/user/aimmds
https://www.youtube.com/watch?v=SCV_m91mN-Q
http://www.yourhormones.info/glands/thyroid-gland/

Next will be - the effect of anabolic steroids on the thyroid hormones and ultimately the metabolism.

Detection of Rutin test in Tea - (Qualitatively)

noreply@blogger.com (Ahmed Ashraf) — Fri, 19 Jan 2018 00:44:00 +0000

Detection of Rutin

Qualitatively detected

Introduction

Rutin is an example of flavanones/flavanoids which should give you the impression of being an antioxidant substance, it is found in a number of fruits and vegetables, it has a wide range of health benefits such as being anticarcinogenic and anti-inflammatory effects.

Chemical structure of Rutin
quercetin-3-rutinoside

Rutin is composed of a disaccharide ( Rhamnose + glucose) glycosylated with a quercetin group ( which is a plant polyphenol compound )

Protein disulfide isomerase is an essential enzyme in protein folding that is synthesized in the endoplasmic reticulum of our cells & platelets and its function is to catalyze the formation and breakage of disulfide bonds - the function of such enzyme is sort of a mixed blessing where performing its job inside the cell is a good thing but when it goes outside the cell it becomes lethal where it can clots proteins which can then accumulate inside the blood vessels, blocking them, ultimately causing Blood clots.

Beside other compounds tested, Rutin was found to be the perfect one to be the inhibitor of Protein disulfide isomerase (PDI) and at the same time it's structure prevent it from entering the cell or otherwise, it would roam around inhibiting any nearby enzyme, so it was said to be anti-thrombotic activity.

Foods rich in Rutin

Onion
Tea
Apples
Citrus fruits
Buckwheat

Tools

Graduated cylinder (preferably 50ml.)
2 Droppers
Ferric chloride solution
2 test tubes, one kept as a control and the other the test.
Source of flame

Procedures

Weight 1 gram of tea (rutin source)
Add 50ml. of water in a boiler, and leave it till it starts to boil
The onset of boiling put your 1 gram tea.
Leave it to boil for five minutes.
After five minutes of boiling, cool the mixture.
Transfer 1ml. of your tea solution in each of your 2 test tubes.
Add few drops of ferric chloride solution to the test tube and leave the control tube blank.
Record your observation.

Result

An olive-green color should be formed as a positive result for the detection of Rutin in tea.

A positive result can be seen in the upper (test) tube comparing it to the control tube

References

Food chemistry 15306
https://news.harvard.edu/gazette/story/2012/05/flavonoid-compound-can-prevent-blood-clots/
https://harvardmagazine.com/2012/09/curbing-clots
https://www.healthline.com/health/potential-benefits-of-rutin#diet
https://www.medicinenet.com/rutin/supplements-vitamins.htm
http://www.phytochemicals.info/phytochemicals/rutin.php
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3739031/

Thanks a lot for reading, I hope you find it informative

#WeliveWelearn

Ed and Rhizopus stolonifer, an agony tale

noreply@blogger.com (Ahmed Ashraf) — Thu, 13 Jul 2017 00:56:00 +0000

Mycology #2

Rhizopus stolonifer (Bread mold)

under general environment

Rhizopus stolonifer has grown on a piece
of bread - the black spots indicate the
formation of sporangium (spore sac)

The fungus was grown under general environment, a piece of bread was cut, put in a small box containing some water, which accelerated the growth of Rhizopus stolonifer or in other words the black mold which usually attacks bread.

It is considered to be a mesophilic fungus since it rapidly grows between temperatures of 15*C - 30*C.

It's classification, Division: Amastigomycota

Sub-division: Zygomycotina

Class: Zygomycetes

And this class by which this fungus belongs to are characterized by

Terrestrial.
Doesn't form any type of swarm spores ( they are spores that have mobility function (motile) which has a flagellum used for locomotion)
Spores are dispersed either by air or by soil.
Each fungus consists of mycelium ( somatic structure of the body) which form filamentous hyphae have large proportion of chitin) - Mycelium is a network of hyphae
The cell wall is formed of chitin
Saprophytic ( little parasitism on plants and animals )
Reproduce asexually by sporangiospores which are non-motile formed within sporangium (sac) reproduce by conidia ( single or chain cells present on the top of conidiophores)
Reproduce sexually by Zygospore due to 2 sex organs similar in shape, size, and aren't differentiated from each other but physiologically different.

The following pictures discuss the structure of the fungus under microscope ( made by me)

Sporangiophore and sporangium

Structure of Rhizopus stolonifer under microscope

Life cycle of Rhizopus stolonifer

Source: http://bioweb.uwlax.edu/bio203/2011/olbrantz_chri/reproduction.htm

Source: Microbiology course no. 07201

Detection of Catalase in potatoes

noreply@blogger.com (Ahmed Ashraf) — Tue, 11 Jul 2017 20:28:00 +0000

Detection of Catalase

Catalase + H2O2 ----------------> water + oxygen

Catalase enzyme is usually found in every oxygen-dependent organism's cells, which catalyzes the decomposition of hydrogen peroxide into water and oxygen, transforming the lethal hydrogen peroxide which is produced normally from the metabolism carried out by our cells into non-lethal compounds ( water & oxygen)

Catalase not only decompose hydrogen peroxide, But compounds like hydrogen peroxides belongs to a category called ''Reactive oxygen species'' or ROS, they are oxidizing species of high energy, containing oxygen, unstable, easily react with other chemical compounds like our DNA damaging it, They are often radicals meaning they contain unpaired electrons such as H2O2, OH ( hydroxyl radical ), and superoxides.

They are produced by cleavage of water with ionizing radiation (ultraviolet and higher energies). They are also normally produced in cellular metabolism and immediately destroyed by other enzymes, but many pollutants, such as tobacco smoke, cause increase in their production - when more is produced than can be removed, they have time to cause DNA damage.

The bubbles produced are the oxygen molecules due to
decomposition of hydrogen peroxide

Tools

Hydrogen peroxide bottle
Test tube
Dropper
Small pieces of cut potato so they can fit inside the test tube

Procedures

Cut very small pieces the size of the test tube's diameter you are going to perform the test in so they can fit inside.
Use your dropper to take a few milliliters of hydrogen peroxide like 3 to 5 ml.
Put the small pieces of potato inside the test tube then pour the content of the dropper inside and watch the reaction performed.

Potatoes are living plant tissue even when harvested so they do respire oxygen normally after being harvested so they have Catalase which when hydrogen peroxide is poured onto it, it will start to bind to the hydrogen peroxide forming a complex that will decompose the hydrogen peroxide to water and oxygen making it non-lethal.

I hope you gentlemen and ladies find this informative and if you do please do share it with your science buds and follow my blog for new topics.

I will upload a complete video explaining all the steps in case you find something difficult or how you going to perform this test at home - so the video COMING SOON...

Recent topic - https://allaboutbiologyworld.blogspot.com/2017/06/cell-division-mitosis-meiosis-comparison.html
https://allaboutbiologyworld.blogspot.com/2017/07/cob-clot-on-boiling-test.html

#Biology #Catalase

#WeliveWelearn

C.O.B - Clot On Boiling Test

noreply@blogger.com (Ahmed Ashraf) — Mon, 10 Jul 2017 21:45:00 +0000

Dairy Science

Clot . On . Boiling Test

Determination of Milk Acidity

Introduction

The normal pH of a natural milk produced ranges from 6.6 to 6.8 and of an acidity 0.13 to 0.18, this acidity is called the Natural Acidity due to some constituents which make up this acidity in milk such as Casein ( composed of α-casein, β-casein, and γ-casein), Whey protein ( composed of Lactoglobulin and Lactoalbumin), Salts ( e.g., Phosphates, Citrates, Nitrogen, Potassium, Zinc, Boron, etc...) and CO2

Leaving milk under normal temperature such as room temperature, this allows for the growth of bacteria present in the milk especially the Lactic acid bacterial strains which converts the Lactose ( milk sugar) to Lactic acid by fermentation decreasing the pH and increasing the milk acidity, and this acidity is called Developed Acidity; Because it came/rose or developed from an organism which is in our case the Lactic acid bacteria.

There are qualitative and quantitative methods of acidity determination for milk bulks in factories/plants and usually we measure the acidity by measuring lactic acid percentage, and in this case we call it '' Total Titratable Acidity ''.

Why do we need to determine acidity in milk?

Because it is important for the manufacture of some dairy products, quality of milk, and the milk stability during some technological treatments.

Clot . On . Boiling Test

It is a qualitative method of acidity determination in milk, we conclude from the test name is that we are counting on the formation or the appearance of Clots in the milk sample, so the milk will be clotted if acidity is 0.25% and more

Tools needed ( Home )

Pipette
Beaker ( will be used as a hot water bath)
Test tube
Milk sample
Flame source

Procedures

Put 5 ml. of milk in clean test tube.
Put the test tube in boiling water bath until boiling of the sample.
Notice the presence of clots, if present it will be positive result, If not, then it will be a negative result.

+ve result - By me

The formation of clots indicates the high acidity of the milk, and perhaps you could ask how I received an acidic milk sample:

Basically, I took like an amount of 200 ml., and a tablespoon of yoghurt ( containing a Lactic acid bacteria Bifidobacterium sp., and Lactobacillus sp.), and left them for about a day in room temperature until a curd was formed. Yet the whole sample wasn't curd, Once a curd was formed I managed to take 5 ml. and perform the test.

I hope you gentlemen and ladies find this informative and if you do please do share it with your science buds and follow my blog for new topics.

I will upload a complete video explaining all the steps in case you find something difficult or how you going to perform this test at home - so the video COMING SOON...

Next one in our dairy science episodes laboratory work experiments will be the quantitative method of milk acidity determination..., the scientific method. STAY TUNED

Recent topic - https://allaboutbiologyworld.blogspot.com/2017/06/cell-division-mitosis-meiosis-comparison.html

#Biology #DairyScience

#WeliveWelearn

Cell division - Mitosis & Meiosis comparison

noreply@blogger.com (Ahmed Ashraf) — Wed, 28 Jun 2017 10:28:00 +0000

Mitosis Vs. Meiosis

Points of comparison	Mitosis	Meiosis
Stages	Lasts in 4 stages	Lasts in 8 stages
Separation of chromosomes	Identical chromatids separate as independent chromosomes	Homologous chromosomes ( each with 2 chromatids ) separate
Pairing of chromosomes	No pairing occurs	Pairing occurs to form tetrads
Number of the resulting cells	2 diploid cells (2n each)	4 haploid gametes ( n each)
Occurs in	Somatic cells	Gonads
Crossing over	Does not occur	Occurs
Chiasmata	Does not occur	Observed during Prophase l and Metaphase l
Prophase
Resulting genetic characters	Identical in each cell & as the mother cell	Each gamete has different characters due to crossing over which allows for genetic variation
Karyokinesis	Occur in Interphase	Occur in Interphase l
Cytokinesis	Occur in Telophase	Occur in Telophase l and in Telophase ll
Phases happen	Once	Twice
Prophase	It usually takes a couple of hours, and therefore it is simple	It takes longer time comparing to the one in mitosis up to a day, and therefore it is complicated
Synapsis	Does not occur	Happens in homologous chromosomes during Prophase
Chromosomal arrangement during metaphase	Chromosomes arrange in one row and centromere divides	Chromosomes arrange in 2 rows & centromere does not divide ( Meiosis I )
Location of occurrence	In plants: growing tips ( apical meristems in shoots and roots) & cambium layer ( meristematic cells) which give rise to xylem and phloem tissues In animals: all cells except nerve cells	In plants: anthers & ovaries of flowers In animals: testis & ovaries.
Considered to be	A building method of the human body especially in the phases of early development (during Zygote stage - Mitosis is so active then it continues to be active after delivery until it becomes regular) replenishing method for worn out tissues or regeneration of new layers such as your skin epidermal layer. It is also considered as a reproduction method for some organisms ''Asexual reproduction''	Aims for the reduction of the chromosomal number and genetic variation of organisms - it is carried out by higher advanced organisms in life ''Sexual reproduction''
Discovered by	Walther Flemming	Oscar Hertwig ( described by him for the first time) then by Edouard Van Beneden ( described it for the second time)
Diagram

**************The End**************

Notice: All pictures inside this topic doesn't belong to me - copyrights goes to the owner:

http://bio1510.biology.gatech.edu/

http://www.ducksters.com/science/biology/cell_division.php

https://www.pinterest.com/peggleston22/science/

local-brookings.k12.sd.us

Recent topics

Difference between animal and plant cells

http://allaboutbiologyworld.blogspot.com/2017/06/difference-between-animal-and-plant.html

Overview of plant cells - part 1 Structure and function

http://allaboutbiologyworld.blogspot.com/2017/06/overview-of-plant-cells-part-1.html

Difference between Eukaryotes and Prokaryotes

http://allaboutbiologyworld.blogspot.com/2017/06/a-comparison-between-prokaryotes-and.html

Difference between Animal and Plant cells

noreply@blogger.com (Ahmed Ashraf) — Tue, 27 Jun 2017 04:25:00 +0000

Animal cells Vs. Plant cells

Points of comparison	Animal cell	Plant cell
Shape	Irregular due to possessing only cell membrane	Rigid in shape due to cell wall which consist of compounds that give the cell wall its rigidity
Organelles	Has centrioles, and lysosomes Small vacuoles relative to those found in plant cells Lack chloroplasts and cell wall	Has chloroplast( organelle containing pigment chlorophyll which gives the plants their green color), cell wall and central large vacuole. Lack centrioles
Totipotency	Only special types of cells can regenerate or differentiate to specific type of cells '' these cells are stem cells'' (Embryonic stem cells (Pluripotent) & somatic stem cells ( adult stem cells or multipotent stem cells)	Can originate a whole new complete plant from any single cell
Genes	All genes are found in all cells but not all of them are active e.g., Insulin-producing gene is active in the pancreas and inactive in your lung cells	All genes are active since they have the ability to regenerate from one single cells a complete plant ''Totipotency''
Metabolism	Animal cells cannot perform photosynthesis since they lack chloroplasts	Plants have one specific different process in their life cycle that no other organisms has it ''Beside some algae and bacterial strains'' Which is the photosynthesis due to chloroplasts
During mitotic cell division	In Prophase, a centrosome ( has 2 pairs of centrioles) is found near the nucleus. Each centriole moves to one end of the cell forming spindle fibers. In Telophase, As the nucleus is now completely divided, the cytoplasm start to divide, a constriction appears & continues in the middle of the cell dividing it into 2 cells.	In Prophase, No centrioles are found. Spindle fibers are formed directly from the cytoplasm In Telophase, No constriction, a middle lamella is formed to separate the formed cells. The middle lamella is in the form of a chain of fine vesicles followed by the precipitation of pectic compounds and then cellulose is followed forming the cell wall separating plant cells.
Nucleus	It is usually in the middle of the cell	It is usually not centered due to the relatively large size of the central vacuole taking up much space.
Starch granules	Absent - excess glucose is usually connected together in chains forming chains of glycogen which are stored in skeletal muscles and liver for later use	Present
Diagram

Recent topics

Overview of plant cells - part 1 structure and function -http://allaboutbiologyworld.blogspot.com/2017/06/overview-of-plant-cells-part-1.html

Difference between Eukaryotes and Prokaryotes http://allaboutbiologyworld.blogspot.com/2017/06/a-comparison-between-prokaryotes-and.html

Animal cells - structure of the organelles and their functions

http://allaboutbiologyworld.blogspot.com/2017/06/our-cell-1-structure-function-division.html

Biology gallery #2 - http://allaboutbiologyworld.blogspot.com/2017/06/biology-gallery-2.html

Overview of plant cells - Part 1 Structure and function (Cell wall and Pits)

noreply@blogger.com (Ahmed Ashraf) — Tue, 27 Jun 2017 00:54:00 +0000

Plant cells

Structure and function

Introduction

Plants are endowed with very unique structures and techniques that help them live a different way of life than us, they have their own immune system and way of defenses methodologies, way of taking up their nutrients, the source of their nutrients, different organs that we do not have and much more we are going to explore in this episode and the upcoming ones as well....

So to begin with, the term cell was firstly used by the English Botanist Robert Hooke to determine the individual unit of the honeycomb-like structure in cork under the compound microscope in 1665.
(Read more about his biography at ---> http://www.ucmp.berkeley.edu/history/hooke.html)

Botany is the scientific study of plants ( and many organisms previously thought to be plants). There are various subfields or sub-disciplines of Botany which may be pure or applied Botany.

Pure Botany
Morphology ( study of plant form)
Physiology ( study of the functions of plant organs)
Anatomy ( study of plant structure)
Taxonomy ( is the science that finds, describes, classifies, identifies, and names plants)
Ecology ( interactions with the environment)
Phytogeography ( The study of the geographic distribution of plants. Also called geobotany)
Genetics ( the study of heredity and variation in organisms)

Applied Botany: Study of the relation of plants with man.
Agriculture The science, art, and business of cultivating the soil, producing crops, and raising livestock; farming.
Horticulture The science or art of cultivating fruits (Pomology), vegetables (Olericulture), flowers (floriculture), or ornamental plants.
Agronomy Is the science and technology of producing and using plants for food, fuel, feed, fiber, and reclamation.
Phytopathology ( plant pathology) is the scientific study of plant disease.
Forestry - The art and science of managing forests, tree plantations, and related natural resources.
Plant breeding - The art and science of changing the genetics of plants for the benefits of mankind.

What are plant cells?
Plants are eukaryotic ( true cells meaning they have organelles) multicellular organisms that composed of millions of cells each of which has its own specialized functions.

What makes plant cells differ from animal cells?
Plant cells have some distinct organelles and structures that aren't found in animal cells. For example,
1)Chloroplasts which are just one type of the various plastids that can be found in a plant cell, Basically, these powerful organelles that are essential for every plant and mainly contributes to the color of the plant which is the green color that everyone sees due to the pigment contained within the chloroplasts' thylakoids the chlorophyll.
Chloroplasts are spherical to oval-shaped structures, double-membraned, green in color due to pigments contained in such as Chlorophyll A and B, etc..
(Pic. source: http://journal.frontiersin.org/article/10.3389/fpls.2013.00114/full)

Chloroplast

Also, it can vary in shape in many species, For example, Zygnema sp. a type of algae in Phylum: Chlorophyta, has a star shaped chloroplast

Zygnema sp.

Cup-shaped chloroplast in Chlamydomonas sp., Phylum: Chlorophyta

Chlamydomonas sp.

Spiral-shaped chloroplast in Spirogyra sp., Phylum: Chlorophyta

Spirogyra sp.

Besides its various types, it also has a major role in plant cells in their life cycles since it performs one of the processes that is ONLY unique amongst plants and some other bacterial cell types which is the Photosynthesis '' Photo = light, synthesis= manufacture or to make something out of'' ****We will have a complete topic about it discussing anything concerned with plastids, chloroplasts, photosynthesis, and Calvin cycle.**** However, We can define photosynthesis briefly in this well-known equation:

6CO2 + 6H2O + Light (energy coming in the form of photons)---> C6H12O6 + 6O2

Photosynthesis

2)Central vacuole, in plant cells the vacuoles are pretty much large in size which also contributes to the shape and rigidity of plant cells due to its large size relatively compared to that of in animal cells which are very small in size and sometimes they lack a vacuole in animal cells, so the central vacuole is large in size irregular in shape to ovale, membrane-bound by a Tonoplast - Functions as enzyme storage and waste removal.

(Pic.,source: http://fig.cox.miami.edu/~cmallery/255/255hist/255methods.htm)

3)Cell wall is what gives a plant its rigid texture, erect structure ( there are exceptions e.g. weak stemmed plants which have some modifications to hold itself erect)and strong structure.

The cell wall is composed of polysaccharide compounds such as mainly cellulose ( Monomeric unit: Beta 1-4, D-glucose units) thousands of them making up the cellulose, hemicellulose, and lignin.

The cell wall is made up of middle lamella, primary wall, and secondary cell wall.

The middle lamella is the first layer formed during cell division, it is shared by adjacent plant cells, consist of pectic compounds and proteins.

Primary wall of the cell wall, made up of cellulose microfibrils embedded in a gel-like matrix of pectic compounds, hemicellulose, and glycoproteins - the primary wall have thinner areas in their structure which are called pit fields, they contain small openings in the wall through which cytoplasmic extensions are known as plasmodesma (singular word., plural is plasmodesmata) by which a very process is carried out through it..... cell-to-cell communication.

Secondary cell wall which is three-layered and by far is the thickest one amongst all cell wall components due to the more cellulose, hemicellulose and lignin content making the plant which developed a secondary cell wall extremely rigid and tough.

In comparison to animal cell, they have relatively small vacuoles, sometimes they lack it, they have centrioles which are used during cell division to form the spindle fibers.

Pits and their types
The pits again are due to the primary walls which form the holes or openings in the plant cells for cell-to-cell communication ''plasmodesmata'', pits have various types and some are subdivided into other types ( simple pits and bordered pits)
(Pic., source: https://sites.ualberta.ca/~hacke/Lenka-profile.html )

Simple and bordered pits

(Pic.,source: http://www.biologydiscussion.com/eukaryotic-cell/cell-wall-of-eukaryotic-cells-structure-and-function/5890)

Note:

If 2 simple pits opposite to each other= simple pit pairs

2 bordered pits opposite to each other= bordered pit pairs

simple pit + bordered pit opposite to each other= half bordered pit pair

A simple or bordered pit with no complementary pit field in front of it= blind pit

Different types of bordered pits

Side view of a bordered pit structure

Simple pits - showing transportation within the cell

Upper view of bordered pits structure

Half-bordered pit pair

Pit borders are due to the bending or overarching of the secondary wall of the cell wall, semi-enclosed making a mouth like structure which is the Pit aperture through which the communication happens.

My newly released video is about this overview in case anyone finds it easy to learn from videos

Link - https://youtu.be/t02MT4heQEA

Some other educational videos that might help you which I don't own - copyrights goes to the owners

Khan academy - https://www.youtube.com/watch?v=zdvKhaQxvag (Plant cell walls)

Shomu's Biology - https://www.youtube.com/watch?v=V-Y-FOexHXE ( Plant cell wall structure and function)

A comparison between Prokaryotes and Eukaryotes

noreply@blogger.com (Ahmed Ashraf) — Sun, 18 Jun 2017 04:49:00 +0000

Eukaryotes vs. Prokaryotes

Points of comparison	Eukaryotes	Prokaryotes
Organelles	True celled organisms, has mitochondria, lysosomes, vacuoles, endoplasmic reticulum, etc...	Has less organelles
Genetic material	Contained inside the cell's nucleus associated with histone proteins forming chromatin	Floating in the cytoplasm, has small circular DNA molecules spread in the cytoplasm called Plasmids - has no associated proteins
Nucleus	Present	Absent
Cell size	Large, average size between 10-100micrometers	Small, average size between 0.1- 5micrometers
Cytoplasm	Cytoskeleton exists exists, performs endocytosis and exocytosis	No cytoskeleton, cannot perform endocytosis and exocytosis
Cell division	By mitosis	By binary fission
Sexual reproduction	Involves meiosis	Asexually, transfer of DNA fragments only
Membrane-enclosed organelles	Exists	Doesn't exist
Ribosomes	Larger size 80S, smaller size 70S in organelles	Smaller size 70S
Organisms are	Often multicellular	Always unicellular
Glycocalyx	Present in some cells that lack cell wall	Present as a capsule or slime layer
Motor organ	The motor organ is cilia	The motor organ is flagellum
Respiratory enzymes	Are found in the cytoplasmic membrane	Respiratory enzymes are found in the inner membrane of mitochondria
Nitrogen fixation	Cannot, only through endosymbiotic relation with a nitrogen-fixing prokaryote e.g., Rhizobium sp., Azospirillum sp.	Some bacteria possess the ability to fix nitrogen via the nitrogenase enzyme
Diagram
Example	Our cells (animal cells), fungi, plants, protists and algae	Bacteria and Archaea

Vote down below in the reaction poll or you can comment to tell me your opinion concerning this comparison.
Latest topic - http://allaboutbiologyworld.blogspot.com/2017/06/our-cell-1-structure-function-division.html
Thanks a lot

Biology gallery #2

noreply@blogger.com (Ahmed Ashraf) — Fri, 16 Jun 2017 06:31:00 +0000

Pituitary gland

Structure of nephron

Chloroplast

Prokaryotic cell (=e.g. bacterium)

Seminiferous tubule

Plant cell structure

Seminiferous tubule

Structure of sperm, abnormalities, and properties

Biology gallery part 1 - http://allaboutbiologyworld.blogspot.com/2016/08/biology-gallery.html

Our cells #1 - ( structure, function, division, disorder & cycle )

noreply@blogger.com (Ahmed Ashraf) — Tue, 13 Jun 2017 21:07:00 +0000

Animal cell

Part1

Structure and function

Simple figure of eukaryotic cell

Introduction

Cellular Level of Organization

The Cell Theory

In the 1830s, Matthias Schleiden studying plants and Theodor Schwann studying animals independently declared these organisms were made of cells. All organisms, both unicellular and multicellular, are made up of cells. cells are the smallest units of living matter and are the structural and functional units of all organisms. Rudolf Virchow declared cells come only from pre-existing cells. So, Cells are capable of self-reproduction.

Cell size, Cells range in size from a frog's egg ( one millimeter) down to one micrometer. Cells need a surface area of plasma membrane large enough to adequately exchange materials.

Note: Largest human cells are the Ovum ( Egg cells) about 120 micrometers, skin cells 30 - 35 micrometers, red blood cells about 5 micrometers and sperm cells which are considered to be the smallest ranges from 4 to 4.5 micrometers

Surface-area-to-volume ratio......dictates that cells must be small

As cells get larger in volume, surface area relative to volume decreases. Size limits how large the actively metabolizing cells can become. Cells that need greater surface area use modifications such as folding and microvilli.e.g, Macrophages ( a type of our innate immune cells that functions as a cell-eater, it can devour many bacterial cells). We have 2 major types of cells, Prokaryotic and Eukaryotic

Prokaryotic cells

All prokaryotic cells lack a nucleus and are smaller and simpler than eukaryotic cells. Prokaryotic cells were the first cells and date back to earliest evolutionary history; Because they are biochemically different, prokaryotes are divided into 2 domains: Bacteria and Archaea

Eukaryotic cells

Eukaryotic cells are members of the domain Eukarya, including kingdoms Fungi, Animalia, Plantae, and Protista. A membrane-bounded nucleus houses DNA. The nucleus may have originated as an invagination of the plasma membrane.

The structure of our cells

-Organelle.., word named on organs with a considerable small size which is why it is mainly introduced to cell organs, they are membrane-bounded organelles ( consisting of phospho-bilipid layer) just like the own membrane of the cell, this membrane separates the organelle from the area around it inside the cell.

-A single cell contains many organelles that provide various and crucial functions to our body, the group of cells comprise tissue, a group of tissues makes up an organ, many different organs builds up a body so we conclude that cells are our building units but what is inside this cell?

To begin with, a cell contain lysosomes, mitochondria.p,(mitochondrion.singular,), vacuoles, nucleus, endoplasmic reticulum ( smooth & rough ), Golgi apparatus, ribosomes, centrioles, cell membrane and last but not least cytoplasm)

1) Golgi apparatus, named after the Italian scientist Camillo Golgi, it is a curved like rod/ banana-like which is like long hallways for receiving proteins and manufacturing vesicles for them, its function is mainly about transporting. (Pic.source: http://www.sciencephoto.com/ )

2) Nucleus, the headquarters of a cell, the mastermind of a cell surrounded by a nuclear membrane, a densely packaged chromatin found inside of it ( our genetic material) which can be unfolded reaching up to 2 meters, chromatin ( is the double stranded DNA + histone proteins which is responsible for the dense packaging to fit inside) the nucleus average diameter is 6 micrometers, nucleolus is a part of the nucleus through which the ribosomes are manufactured. (Pic.source:https://epiehonorsbiology.wikispaces.com/Nucleus2?responseToken=0d241e85e112dc01d3c1c27fa3ee7cfdc)

3) Mitochondrion, spherical body, with outer and inner membranes ( intermembrane space found between them ) folded from the inside, area inside the folds is called Matrix while the outside is the crista, has ribosomes and its own DNA ( it is an independent organelle ) 0.5 to 2 microns in length (Pic.source: http://faculty.une.edu/com/abell/histo/histolab2.htm)

Mitochondrion simple anatomy - made by me

4) Lysosomes, membrane-bounded organelle, small-rounded bubbles containing essential enzymes manufactured by the endoplasmic reticulum. (Pic.source: http://quatr.us/biology/cells/lysosome.htm )

5)Vacuole, a space or vesicle within the cytoplasm of a cell, enclosed by a membrane and typically containing fluid. (Pic.source: http://www.mstworkbooks.co.za/natural-sciences/gr9/gr9-ll-01.html )

6)Endoplasmic reticulum ( rough and smooth ), mainly a network of flattened minute tubular or irregular in shape and branches and are surrounded by thin membranes found in the cytoplasm forming many folds, RER ( rough endoplasmic reticulum) named rough due to the attachment of ribosomal units on its membranes, SER ( smooth endoplasmic reticulum) named smooth due to the absence of ribosomal units, the ribosomes appear like dots on the surface of the endoplasmic reticulum ( rough ) - it is the second organelle after nucleus in its volume as it takes over a remarkable volume in the cytoplasm )
(Pic.source: https://www.uni-mainz.de/FB/Medizin/Anatomie/workshop/EM/EMSERE.html
http://www.cellimagelibrary.org/images/37237)

7) Ribosomes, are small rounded circular units mainly built of RNAs, spread all over the cell in many numbers and are found on endoplasmic reticulum giving it its rough structure, has many types tRNA, rRNA and mRNA. (Pic.source: https://www.uni-mainz.de/FB/Medizin/Anatomie/workshop/EM/EMVokabular/EMR.html )

8) Centrioles, cylindrical/rod-like structures found nearby the nucleus of animal cells, they perform major functions during cell division - they have the ability to produce thin fibres known as spindle fibers, its outer wall contains a number of microtubules arranged in 9 groups each of them is formed of 3 microtubules - 0.2 to 0.8 micrometre in length and 0.2 micrometres in diameter.
(Pic.source: http://www.biology-pages.info/C/Centrioles.html )

9)Cytoplasm, It is the swimming pool for all the previous organelles, it is where the organelles are kept inside, proteins to be vesicled are found, ribosomes are distributed everywhere - jelly-like substance, a water-based solution containing that contains ions, small molecules, and macromolecules-
(Pic.source: https://www.uni-mainz.de/FB/Medizin/Anatomie/workshop/EM/EMCytoplasmaE.html )

10) Cell membrane, Phospho-bilipid layer, consists of hydrophilic head ( hydro= water, philic= loving or attracted ) and hydrophobic tail ( means water-repellent), our cell membrane has a lot of contributions to our body, it functions in homeostasis, transporting substances due to its semi-permeability and being the main reason of cell signaling due to the presence of membrane-bound receptors on the surface, glycoproteins (receptor function), integral and peripheral proteins

Functions

-The cell, which is generally the building unit of our body, its itself being the building unit makes a major function since it has many types, connective tissue forming cells, muscular-forming tissue cells and as well as all of our organs with a few differences, the true cell ( eukaryotic) contains as we know its organelles, each of which has its own function and together all working properly makes up a powerful bio-machine ( cell ) a cell contains more than 50 thousand different proteins essential for its vitality and viability throughout its entire life.

-A group of cells together forms a tissue, Moreover, a group of tissues makes up organs, Last but not least, different organs constructs the human body; so as a conclusion, cells are the basic building units but what really makes it the basic structural unit of the human body.

-Basically, from the previous point we discussed the structures of a cell and known that it has organelles, these organelles are the main reason we keep saying that a cell is the building unit of the human body due to the following vital functions carried out by these organelles:

Mitochondria, it is the powerhouse of the cell as they contain respiratory enzymes, present in both animal and plant cells, energy-rich molecules known as ATP ( adenosine tri-phosphate) are formed and stored in reduced forms known as NADH2 (Nicotinamide adenine dinucleotides) for further use, this organelle has its own DNA meaning it is independent of the cell's nucleus, it doesn't have to follow division if the cell is carrying division, the production of ATPs is carried out by a process known as Krebs cycle (named after the scientist who discovered it Hans Krebs) a.k.a tri-carboxylic acid cycle a.k.a citric acid cycle, Furthermore, this cycle is carried out aerobically ( In presence of oxygen ), Last but not least, such process produce 2 molecules of ATP, 8 molecules of NADH2 and two molecules of FADH2 ( flavine adenine dinucleotide )
Nucleus, it is the most important structure in a cell, it contains the genetic material ( DNA ) which encodes all the essential and required proteins for the cell to thrive and survive, In the nucleus a chromatin reticulum which is the DNA + histone proteins bound together, it condenses right before the initiation of mitosis in case of cell division to nucleosomes scale level in order to launch the division, also it is where transcription occurs ( a process of which the cell's own DNA acts as a template in making Messenger RNAs ( mRNAs) which is supposed to be the cell needs, inside of this nucleus a large circular portion called nucleolus which is where ribosomal RNAs are synthesized, If our body is in need of a specific combination of proteins/amino acids then such organelle (nucleus) is the one responsible for this job, Besides, the DNA ( genetic material) holds all our phenotypic and genotypic characteristics ( everything) whether if some are in active or inactive form.
Golgi- apparatus, it receives anything whether synthesized from nucleus, in cytoplasm and is needed to be expelled out of the cell, from the endoplasmic reticulum, it packages it in vesicles (rounded structures) so they can be soon sent to the outside inside the vesicles or disintegrated and released into the blood in some cases.
Centrioles, these small structures has a great role during cell division, with which it forms the spindle fibers as we know them which binds with chromosome during the phases of cell division and starts pulling them to provide copies of cells having the same and equal genetic material in case of Mitotic cell division or reduction of this genetic material in case of Meiotic division.
Ribosomes, they have various types mRNA, rRNA and tRNA types of ribosomes, each of which has its own function, all ribosomes contribute in DNA transcription ( which is a process of changing DNA into RNA or to be more clear mRNA ( messenger RNA) and translation which is, in other words, mean ''protein synthesis'' production of amino acids connected to each other by peptide bonds forming a polypeptide chain (proteins), rRNA ( ribosomal RNA) these are units of ribosomes main job is to read the mRNA and provide message for the tRNA ( transfer RNA) to perform its function which is getting the specific amino acid (anti-codon) for the specific (codon - the name of the bases in mRNA) **There will be a whole topic covering all what you need to know about Ribosomes since they have a lot of information**
Lysosomes, are the digesting units of an animal cell, containing degrading enzymes enclosed in membranes, such organelles work on breaking down any cellular wastes, renew materials and also they are found more in immune function cells contributes in killing any intruders ( e.g. bacteria) by releasing its enzymes on these foreign bodies, They are more abundant in animal cells ( e.g. cells of liver, kidney and small intestines) than plant cells
Plasma (Cell) membrane, Every cell is surrounded by a membrane which protects its constituents and regulates the relationship between the cell and its surroundings. It also regulates the passage of substances into the cell and out of the cell - it described as a mosaic fluid, due to its selective permeability it regulates the passage of the nutrient materials, thus enabling the cell to choose what it needs from different materials, these substances move through the plasma membrane by diffusion, active transport and phagocytosis - contributes to homeostasis (internal temperature of the body which is normally 37*C) and regulation of electrolytes in the body - cell signaling due to the presence of receptors such as glycoproteins which play an important role in the communication between cells such as antigen-presenting cells to immune cells in order to identify the target vector, or the secretion of any type of substances in order to alert other cells of presence of foreign invaders such as Cytokines produced by Helper T cells in the field of invasion. **We will have a whole topic about Cell signaling since it is so interesting topic**

Fluid mosaic model of the cell membrane
source: http://www.macroevolution.net/fluid-mosaic-model.html

Endoplasmic reticulum, It can be found adhered to the plasma membrane of the cell, It may also extend between the cells in order to communicate with the membranes if the neighboring cells. In this way, all the cells are connected to each other through their endoplasmic reticula. In addition to it plays a part in the formation of secretions in the cells, also the ribosomes on its surface are responsible for protein synthesis. Moreover, it acts as an internal transport system that connects together the various parts of the cytoplasm with the nucleus and also with those of other cells.
Cytoplasm, It functions like the bedding material, the fluid which holds all the cell organelles together also contributing to the shape of the cell, extending from the nucleus to the plasma membrane in eukaryotes, due to its cytoskeleton ''a.k.a cytosol'' a network of fibers about the whole cell giving it shape also organize these cellular components. Elements making this cytoskeleton include actin filaments, intermediate filaments, and microtubules.

Actin filaments are long, thin fibers ( about 7 nanometres in diameter) that occur in bundles or meshlike networks. Actin filaments move by interacting with myosin: myosin combines with and splits ATP, binding to actin and changing configuration to pull actin filaments forward.
Intermediate filaments are 8-11 nanometers in diameter, between actin filaments and microtubules in size. They are rope-like assemblies of fibrous polypeptides. Some support the nuclear envelope; others support plasma membrane and form cell-to-cell junctions.
Microtubules are small hollow cylinders (25 nanometres in diameter and form). and are composed of a globular protein tubulin.

Cell Vacuole, It helps in storing the wastes resulted from metabolic reactions or any cell activity and removing them in order to protect the cell from any damage due to the accumulation of wastes.

Thanks everyone, I hope you find this informative and if you do please subscribe, comment any questions if you have or perhaps if you would like to share your opinion with me either by writing in comments or voting the poll you will find below every topic I do, don't forget to share it with every biologist :) it really help me out and cheer me up.

#WeliveWelearn

#Biology

Check out my latest topic at -----> http://allaboutbiologyworld.blogspot.com/2017/06/pituitary-gland.html

For more biology stuff----> allaboutbiologyworld.blogspot.com

Facebook group -----> https://www.facebook.com/biologyclub17/

References

Principles of Zoology course no. 11101

Botany - a classification to Plant kingdom course no. 07102

https://micro.magnet.fsu.edu/index.html

https://www.khanacademy.org/

My highschool biology courses

William Stillwell-An Introduction to Biological Membranes. Composition, Structure and Function-Elsevier Science (2016)

Pituitary gland

noreply@blogger.com (Ahmed Ashraf) — Tue, 06 Jun 2017 00:04:00 +0000

Pituitary gland

Pituitary gland

Pituitary gland is considered as the master gland as it controls the functions and secretion of most of the endocrine glands. The gland is located beneath the brain and in connection with the hypothalamus, The gland consists of 2 parts:

Adenohypophysis: It consists of the anterior and middle lobe - developed embryonically from the roof of the mouth.

Neurohypophysis: It consists of the posterior lobe and a part of the brain called the infundibulum ( a stalk connecting the gland to the brain) - developed from the back of the forebrain.

Note: Hypophysis means Pituitary,..Plural: hypophyses

Hormones of the Adenohypophysis ( anterior lobe of the pituitary gland):

Growth hormone (G.H.)

It controls metabolism especially protein synthesis, accordingly it controls the physical growth of the body.

Hypo-secretion ( Hypo=less or weak) of this hormone during childhood causes Dwarfism and its hyper-secretion ( hyper=over) during the same period causes Gigantism.

Hyper-secretion of G.H. in adults causes Acromegaly which is characterized by increased bone growth at the extremities and characterized by enlarged hands, feet, fingers and bones of the face.

2. Pituitary Trophins:

A group of hormones that affect the activity and secretion of other glands and includes:

Thyrotrophin (thyroid stimulating hormones) (TSH) ---> check out this brief topic about thyroid gland at - http://allaboutbiologyworld.blogspot.com/2016/05/thyroid-gland-brief-notes.html

Adrenocorticotrophic hormone (ACTH) which affects the function of the adrenal (Suprarenal) cortex.

Gonadotrophic hormones - Affect the function of gonads ( ovaries in females and testes in males).

This group includes:

Follicle stimulating hormone (FSH) which affects the growth of the ovarian follicles and formation of Graafian follicles in females and formation of seminiferous tubules, spermatozoa in male.

Lutinizing hormone (LH) which stimulates the formation of corpus luteum in females and the formation and secretion of interstitial cells in the testes of males.

These two hormones are important for sexual maturity as they are responsible for secretion of male and female sex hormones

.

3. Prolactin: stimulates milk formation and secretion from mammary glands ( breasts).

Hormones of the neurohypophysis ''Posterior lobe of the pituitary gland'':

Two hormones are secreted from the nerve cells in the hypothalamus and called the secretary neurons, and reach the neurohypophysis ( posterior lobe of pituitary) through the infundibulum after which they are released to the blood stream.

The two hormones are:

Antiduretic hormone (ADH) (Vasopression):

This hormone increases the re-absorption of water from the kidney tubules and decreasing the volume of urine excreted. In addition it increases blood pressure.

2. Oxytocin:

This hormone affects the uterine contraction and increases it during delivery ( labour). Gynecologists use this hormone to accelerate the birth of a baby by stimulating strong contractions of uterine muscles ( synthetic type '' Pitocin'' of Oxytocin)

In addition oxytocin stimulates the release of milk from mammary glands with the beginning of lactation ( milk letting hormone).

References used:

https://www.accessdata.fda.gov/drugsatfda_docs/label/2014/018261s031lbl.pdf

https://www.khanacademy.org/science/health-and-medicine/advanced-endocrine-system/endocrine-system-introduction/v/hypothalamus-and-pituitary-gland

http://www.audioenglish.org/dictionary/hypophysis.htm

+My highschool Biology book which provided a lot of content.

I hope you ladies and gentlemen like the topic, please if you find it informative like, share and perhaps follow my blog so as to be tuned whenever a new post comes
Thanks a lot
#Biology
#WeliveWelearn
allaboutbiologyworld.blogspot.com

Todd has been sick! Short tale

noreply@blogger.com (Ahmed Ashraf) — Sat, 22 Apr 2017 22:16:00 +0000

Growing Penicillium digitatum on Todd ( an orange )

Under general environment

As you can see the green parts indicates the development of conidiophores
and as well as the fruiting bodies which carry the spores

Under general environment, an orange named Todd was left for a while infront of a window a couple of days and symptoms of fungal infection was seen ( white color ) as the beginning, it indicates the sprouting of spores to hyphae which then forms a network of mycelium and later on forms the fruiting bodies which carry the spores at that time it becomes green in color.

The mold scientific name is Penicillium digitatum

The main causal agent of fruit-rot to citrus fruits ( e,g, orange as in our case) the green mold disease, also it is a major post-harvest disease which should be taken into consideration when harvesting our crop.

A mesophilic fungus which prefers temperatures between 15*C-45*C, of Division: Ascomycota

Following a strict means of clean and sanitized storage, handling and packaging can ensure the least infection, removal of any infected plants quickly before the mold grows and infects other fruits comes in handy, applying specific fungicides in particular concentrations and much more from chemical and biological controls can be found in the following website:http://www.plantwise.org/KnowledgeBank/Datasheet.aspx?dsid=39570

Culturing it, due to the limited resources I have since of my inability to afford tools for culture media, I have used Gelatin, I bought a strawberry Jelly, prepared it and inoculated a sample of the fungi in it and after 5 days leaving the petri dish in room temperature, results were:

My very first culture media

This was Todd after a week from the last picture shown

Needed to be contained

Observing the mold structure under optical microscope

The following clip ( I DON'T OWN IT - Copyrights goes to its owner) shows a fastened footage of the mold on a lemon: https://www.youtube.com/watch?v=W1Bzi7T8-HQ

#WeliveWelearn

allaboutbiologyworld.blogspot.com

Thanks for listening and I hope you follow my blog, sorry for the inactivity but all of this is due to my college's semester, I will be back very soon to post new biology stuff! Stay tuned and support me please :)

Microscope reveals

noreply@blogger.com (Ahmed Ashraf) — Fri, 23 Dec 2016 22:32:00 +0000

Home ant (1)

(2)

Antenna of the ant

Close look to this ant's leg

Plant cells of an onion - stained by iodine ( the only stain I had at the current moment)

A close look to the plant cells of an onion

Cells extracted from the inner lining of my cheeks also stained by iodine

Wing of Culex mosquito

Stinging apparatus of Culex moquito

Legs of Culex mosquito

Mouthparts of Musca domestica (house fly)

Wings of Musca domestica (house fly)

Rhizopus stolonifer (bread mould) sporangium + sporangiophore

Rhizopus stolonifer

Gram-positive Monobacillus

Penicillium digitatum

Peniciliium digitatum

Youtube channel---> https://www.youtube.com/channel/UCmxjb5FPPlAK18iTd-WPnBw
Facebook----> https://www.facebook.com/profile.php?id=1448792543
Follow me for more biology stuff !

Biology gallery

noreply@blogger.com (Ahmed Ashraf) — Fri, 19 Aug 2016 15:49:00 +0000

All the diagrams I have drawn and the ones I am going to will be posted over here so stay tuned and you will see amazing and simple diagrams related to biology.

Simple heart structure diagram

The thyroid gland & it's hormones

Lymphatic vessel & it's histology

Embryo attached to placenta

Capillary beds

Pancreas & Islets of langerhans

The skin- epidermis portion

The skull ( not fully labelled)

Ebolavirus

Mitochondrion structure

Transverse section in kidney

Structure of animal cell

Cross section in quarter Udder

Human immunodeficiency virus (HIV)

Part 2 ----> http://allaboutbiologyworld.blogspot.com/2017/06/biology-gallery-2.html

I hope you guys like them and as always I will keep posting stuff for you biologists out there! stay tuned!!

We live we learn!!!

Ebola - all what you need to know about Ebola

noreply@blogger.com (Ahmed Ashraf) — Sat, 30 Jul 2016 15:28:00 +0000

Family: filoviridae

Viral hemorrhagic fevers

Introduction

Filoviridae means viral hemorrhagic fevers, a very high level of internal bleeding, family consists of two viruses: Marburg & Ebola viruses, Ebola has sub-types: Tai Forest, Sudan, Reston, Zaire & Bundibugyo, the virus concerned with the current outbreaks, is the Zaire species.

Mortality rate is high ranges between 30%sometimes 50% to 90%, depending on the virus, Ebola Reston is considered to be the one with low pathogenicity for humans

History

The virus first recorded in 1976 in ''Yambuku'' democratic republic of Congo it was then known as Zaire & Nzara, South Sudan, it first appeared in Ebola river for which the Ebola virus was named, It presents itself like the flu or malaria, symptoms resulted due to Ebola are severe headaches, diarrhea, vomiting, fever, muscle pain, weakness, stomach pain and bleeding among other things symptoms can appear from 2 to 21 days but the average time is between 8 to 10 days.

In December 2013 in west African countries of Guinea it was later confirmed in March 2014 then emerged to Liberia & Sierra Leone, they became the center of infection and some of these areas 90% of the patients died.

Then the disease prevailed to Europe and USA such as in Texas due to the travels between the cities, by far the cases has been growing more than 21,000 since January 2015.

Due to the several cases happened since 1976, we concluded that most of the countries and regions that have had this epidemic is usually countries of poor infrastructure, low economic level and very bad medical care.

Mortality rates of Ebola virus

Structure & Function

-Diameter: 80nm

-Length: 970nm

-Shape: filamentous, cylindrical or tubular-like, resembles a U-shape or takes the shape of number ''6'', pleomorphism '' as definition is the presence of more than one distinct shape'' (biological feature)

-Lipid( fatty) membrane, with glycoproteins on the surface of the virus as antigens for binding, glycoproteins are any class of proteins with carbohydrate group attached to the polypeptide chain then a viral capsid, ''capsid: a protein shell usually made to surround the viral genetic material'' in our case it is a negative-sense RNA strand '' negative-sense RNAs their genome has to be transcribed as soon as the virus enters the host cell in order to carry out replication''

Ebola virus has of approximately 19,000 base pairs, the 3' terminus is not polyadenylated & the virus encodes seven structural proteins: nucleoproteins (NP) '' are proteins structurally associated or presented with nucleic acids DNA and RNA such as histone proteins, VP35 (polymerase cofactor) in the transcription & replication complex in RNA polymerase also blocks phosphorylation and activation of interferon regulatory factor 3 (IRF3) '' IRF3 briefly is a critical transcriptional factor for the induction of interferons alpha & beta.

VP40 it is the primary viral matrix protein means it organizes, covers and maintains the the virion structure, attached directly to the cell's membrane and provides budding function, in some RNA viruses it acts as a bridge between the membrane and nucleocapsid

GP, glycoproteins we mentioned that before saying they are found on the surface of the Ebola virus, acting as antigens for binding sites. Recall GP as definition? '' proteins attached with it any class of carbohydrate functional groups''

VP30 ''transcription activator'' phosphoprotein (any protein other than nucleic acid & phospholipid attached with it phosphorous) essential for the initiation of the Ebola virus transcription also an RNA binding protein.

VP24 is the secondary viral matrix protein attached beside VP40 '' the primary viral matrix protein'' minor component of the virion, it has a role in the formation of nucleocapsid & effect on transcription and replication of the viral genome, Last but not least, RNA polymerase (l).

Ebola virus anatomy

C.section of close view of Ebola virus

Signs & symptoms of the Ebola virus disease

Symptoms and signs of Ebola virus disease shows up from 2 to 21 days after the exposure to Ebola virus but the average ranges from 8 to 10 days, Ebola virus can kill its own patient within 7 to 14 days after developing symptoms, a person contracted with Ebola virus can be found hidden in his semen up to 7 weeks.

According to the world health organization (WHO), humans aren't infectious until they develop symptoms so whenever you find yourself or someone else developing symptoms of Ebola virus, seek medical care as soon as possible and avoid contact with anyone.

The symptoms developed by a person contract with Ebola are the following:

Headache
Aches in muscles & joints
Hiccups
Abdominal pains
High fever, usually more than 38.5 C*
Sore throat
Weakness
Swelling
Diarrhea
Stomach pains
Internal & external hemorrhage (bleeding)
Fatigue
Chilling
Vomiting
Nausea
Red eyes & bleeding coming out of the eyes
Chest pain and cough
Rash
Kidney and liver failures
Severe weight loss

As we notice, it is very severe, the fatal range of such disease is between 50% - 90%, seeking medical care immediately, obeying the precautions and the good medical care & the will of surviving and the status of the patient's immune response can develop a good recovery from Ebola, developing the suitable antibodies against such disease will help you get over it also such antibodies are said to be at least surviving in your body for 10 years or so.

Two crucial things we are going to talk about next, first the mechanism of prevalence in our body & the steps of replication of Ebola virus.

First: Mechanism of prevalence in our body

Ebola virus directly attacks our immune system, it mainly goes onto one of your important immune antigen presenting cells ''Dendritic cells'' or Langerhan cells & macrophages (guard cells) both are type of your innate immune system cells, these cells have type two major histocompatibility complexes, once it penetrate through the dendritic cell releasing its components inside it starts taking control of it and uses its machinery to build more of itself once not only it infects the dendritic cells but it also trick the anti-viral cells and some specialized cells by sending them messenger proteins that end these cells life prematurely( meaning when they are still in their inactive states), there are cells such as Natural killer cells are present just to hunt down any virus-infected cells by sending enzymes ''granzymes'' which causes holes named ''perforins'' in the infected cell membrane in what we call ''Apoptosis'' (=program cell death).Unfortunately, these cells also gets infected by Ebola virus.

The guard cells such as macrophages and monocytes which are infected are ordered to send messenger chemical proteins ''cytokines'' to the blood vessels to releases its fluids inside our body causing internal bleeding, another areas such as liver, spleen and kidneys which are kind of the organs that maintains and balance our bodily fluids also gets infected by the Ebola virus leading to organ failure but in this case we can call it a massive or huge multiple organs failure besides the lungs which also gets shutdown due to the unstoppable attack of the virus on our immune system, the immune cells launches a cytokine storm at which each immune cell releases a massive secretion of chemical messengers called ''cytokines'' that at such case it affects our organ tissues and blood vessels,Paradoxically, the healthier the immune system, the more damage it can do to itself, so the copious amount of fluids spread all over the body leads to what this family is described by ''hemorrhagic fevers'' the body becomes seriously dehydrated and at this time, the chance of dying is very high.

Luckily, Ebola virus isn't high contagious, the only ways you can contract Ebola is to come in contact with bodily fluids of an infected person such as urine, semen, saliva, mucous, blood, feces or vomit and from fruit bats said to be '' natural reservoirs'' of Ebola virus so a conclusion is that Ebola virus is a type of zoonotic disease '' diseases that can be spread between animals and humans'' such as Dengue, yellow fever, HIV, malaria, Marburg, rabies, swine flu and much more, so other animals can be infected with Ebola since animals feed on each other and one day or another it will come to a fruit bat eaten by any other wild-type animals which people usually hunt down and uses its meat ''bush meat'' and that is one of the reasons why some people contracted Ebola in USA.

Replication of Ebola virus

As we know Ebola virus infects firstly your guard cells & antigen-presenting cells of your body macrophages and dendritic cells, these immune cells surface antigens has something called DC-SIGN (dendritic cells special intracellular ''means inside the cell'' adhesion molecule 3-grabbing non-integrin) also known as CD209 encoded by CD209 gene,adding that it is a C-type lectin receptor (lectins are type of proteins that can bind to the cell membranes, they recognize and bind specific carbohydrates found on the surfaces of cells also plays a role in interaction and communication between cells for recognition) , Glycoproteins surface antigens and receptors of the Ebola virus attaches to the target cell's receptors and eventually binds to it.

The virus then starts penetrating the cell's surface ( endocytosed) later enters an early endosome ''endosomes are membrane-bounded vesicles'' by macropinocytosis also known as clathrin-mediated endocytoses ( cytosis means cell action, pinocytosis is an action the cells do to take up some nutrients by making a folds of its own membrane surrounding the nutrients or whatever molecules it is taking in a vesicle and receptors for binding)Ultimately, the virus glycoproteins receptors binds to the cell's receptors inwardly making an invagination taking the virus inside.

(Clathrin is a protein found on the surface of these cells that has a role in the formation of these vesicles)

Also NP-C1 Niemann-Pick C1 is a hydrophobic (hates water) lysosomal integral membrane that plays an essential role in cholesterol regulation, transport and storage facilitates the entrance of Ebola virus into your cell endosomes and lysosomes, without it the virus cannot leave the vesicles in order to start the infection.

http://www.microbiologyinfo.com/tag/ebola/

The fusion happens when the pH ( concentration of hydrogen ion in any solution) is low or with NPC1 binding.

Once the virus penetrate through the endosomes, it dissolves its outer hull, leaves its genetic material, nucleoproteins and enzymes, transcription phase starts now, RNA polymerase found on the RNA strand of the virus transcribes the RNA strand into seven monocistronic mRNAs ( monocistronic mRNA means an mRNA that codes only for one protein) the cell's machinery now is taken control via the virus which makes it produce the required nucleoproteins, tRNA molecules, etc..

The polymerase slides over the RNA strand 3' to 5' order transcribing the genes into particular proteins.

After translation, replication phase starts at which the negative-sense ssRNA strand acts as template to synthesize a complementary +ssRNA which is then used to synthesize a -ssRNA which is encapsidated with its proteins forming a new virus.

Now the virus is capsidated having its genetic material, nucleoproteins and enzymes inside, it is about time it leaves the cell to continue infecting other cells. Budding phase initiates.

The virus uses the cellular ESCRT (endosomal sorting complex required for ''transport'' ) system '' it is machinery used to control the key cellular processes, the ESCRT proteins functions by binding membrane, generating curvatures and presence of some enzymes to complete the process'' ESCRT has various functions such as its enrollment in cytokineses, the ESCRT family consists of ESCRT -0, ESCRT- 1, ESCRT-ll & ESCRT-lll

ESCRT-0, ESCRT-l & ESCRT-ll functions in deformation of membranes & primarily involved in cargo sorting while ESCRT-lll cleaves (breaks down) the buds' neck from its cytosolic face.Last but not least, the VPS4 disassembles the complex and the virion is free from the cell now.

http://www.microbiologyinfo.com/tag/ebola/

(Cytosolic face is the surface of a bio-membrane ''structure bounding a cell membrane or cell organelle it contains lipids, proteins, glycolipids, steroids and much more'' directed towards the cytoplasm)

Ebola virus replication

Are there any cures found for Ebola virus disease?Vaccines?

Currently no, by far no cures discovered but there are few ways that contribute in controlling and decreasing the infection rate of the Ebola virus in our body such as Intravenous fluids (IV), balancing electrolytes ( body salts), maintaining oxygen status and blood pressure until the body generates a powerful immune response,

Intravenous fluids regulation is carefully made to achieve and maintain an isotonic environment in the body ( used for cases of dehydration) usually when a person's body is dehydrated, fluid containing water and dissolved salts known as electrolytes such as Na & K, there are two types in which intravenous fluids are used: 1) Acute fluid resuscitation 2) Maintenance fluids

-Acute fluid resuscitation, which is important for our case, is used in the cases of hypovolaemia (hypo=low - vol=volume - aemia=anemia or loss) a loss in blood volume e.g. hemorrhage, severe diarrhea & vomiting, burns and much more symptoms like those mentioned in our case (Ebola)

There are three main types of fluids crystalloids which contains small molecules that can easily pass through the membranes of the cell e.g. Normal saline 0.9% sodium chloride, Hartmann's solution and 5% glucose or dextrose.

Hartmann's solution IV

Just a very small example of what some of these crystalloids contain, normal saline 0.9% sodium chloride has sodium 154mmol/L & chloride 154mmol/L.

Other treatments that help you get over Ebola virus which has saved many doctors who unfortunately contracted the Ebola virus from their patients, is a serum made from the blood plasma of other patients or doctors who had contracted and survived from the virus and, then injected into their bodies, which with the proper care later helped them get over the virus and develop an immune response but such thing is considered to be a type of passive humoral immunity since remember? the blood plasma contains immunoglobulins ( antibodies) produced by those whom survived the ebolavirus but still yet researches are ongoing for such type of antibodies and a way to develop a vaccine through this.

Throughout the medicine and this incredible field of science, not only medicine-ways are the ones needed to help one survive any disease but also resistance to fatal disease like this requires the will and your believe in yourself that you can do, thrive and get over such disease beside taking, seeking and obeying medical care sharply will definitely let you defeat such disgusting fatal viruses.
(read this story about one of Ebola virus survivors and how it is inspiring, Dr. Melvin Korkor: http://archive.eboladeeply.org/articles/2014/09/6124/survivor-story-dr-melvin-korkor/)

The following link provides various medical equipment used for Ebola care according to WHO: http://www.who.int/medical_devices/meddev_list_ebola_25nov_en.pdf?ua=1

Last but not least, no matter what happen, the humans has always had and still has an infinite potential of evolution which will succeed in eliminating such disease and consign it in its rightful place..... the history books.

References used:

http://groups.molbiosci.northwestern.edu/holmgren/Glossary/Definitions/Def-M/monocistronic_mRNA.html
http://archive.eboladeeply.org/background/basics/ <-there you can find various journals about ebola
https://deepblue.lib.umich.edu/handle/2027.42/110318
http://www.who.int/mediacentre/factsheets/fs103/en/
http://www.ncbi.nlm.nih.gov/pubmed/10721995
http://www.microbiologyinfo.com/tag/ebola/ (special thanks)
https://micro.magnet.fsu.edu/cells/endosomes/endosomes.html
http://ed.ted.com/lessons/what-we-know-and-don-t-know-about-ebola-alex-gendler
https://www.youtube.com/channel/UCH4BNI0-FOK2dMXoFtViWHw
https://www.youtube.com/channel/UCsXVk37bltHxD1rDPwtNM8Q
https://www.youtube.com/channel/UCPY9IKSkr2GfFW5jbgA5Qbw
http://geekymedics.com/
http://www.washingtonpost.com/wp-srv/special/health/how-ebola-spreads/#b10g15t20w14 <-- check out this simulation showing how deadly Ebola virus is comparing to other viruses
http://www.uniprot.org/uniprot/Q05127
https://collab.itc.virginia.edu/access/content/group/f85bed6c-45d2-4b18-b868-6a2353586804/P/Ch24_Coleman_G_Niemann-Pick_C1/Coleman-NiemannPickC1_NPC1.html
http://www.ncbi.nlm.nih.gov/pubmed/12223058

Videos

1)Discusses the mechanism of infection

2)Facts about Ebola virus
3)Introduction to IV fluids (very informative)
4)Mechanism of spreading ( in a nutshell )
5)What we know and don't know about Ebola
6) Another video to help you mechanism of infection

Overview of immune system Part 4

noreply@blogger.com (Ahmed Ashraf) — Thu, 07 Jul 2016 23:20:00 +0000

Immune system

Continue adaptive immune defenses

Cellular defenses - T lymphocytes

Your immune system last efforts deploys when the invaders made it to the cells, penetrated its membrane and started dividing, now it comes to a cell to cell combat.

T lymphocytes are one of your adaptive immune cells which originates in your bone marrow but matures in thymus gland, a lymphoid organ situated in your neck and becomes small by the time, puberty approaches, it secretes thymosin hormone stimulates the maturation & production of disease-fighting lymphocytes which are T-lymphocytes, there are kind of varieties of T-lymphocytes:

Cytotoxic (killer) T cells, mainly kill/attack viruses, bacteria and infected host cells
Helper T cells, they have a major role on your immune system, these cells are more likely to be the corner stone of the immune system, because of its presence, our immune system wouldn't have been able to identify & respond to any foreign antigens, these immune cells releases chemicals called ''Cytokines'' their secretions stimulates various things that contributes to your immune response:

Activates macrophages from your innate immune system
Causes inflammation
Helps in the maturation and activation of other immune cells such as B-lymphocytes to become plasma cells & present to it the specific antigen of the foreign invader from macrophages in order to produce the specific antibody for it.
Their chemical secretions induces other white blood cells to come to the site of infection and increase the rate of white blood cells.

Suppressor or Regulatory T cells, they have an important function in our immunity, they stop the immune processes when the infection is over in order to avoid any further production of immune cells or continuous immune responses which may lead to autoimmune diseases such as Multiple sclerosis where the white blood cells attack the myelin sheath surrounding the nerve cells or type one diabetes where the white blood cells attack pancreatic cells leading to the dysfunction in production of insulin also suppressor T cells induces plasma cells to save some cells having the information of the foreign invader ''Memory B cells'
Memory T cells, which mainly has memories of the antigens of the specific invaders in case they made a comeback.
Natural killer cell, these are of both types innate & acquired (adaptive) immune cells, they primarily attack infected-host cells by secreting messenger proteins containing ''Granzyme'' they are serine proteases ''enzymes that cleaves peptide bonds in proteins'' released by cytoplasmic granules within the cytotoxic T cells & natural killer cells they induces ''apoptosis'' (program cell death) that produces holes named perforins.

So this is how it goes, your macrophages from your innate immune system after engulfing a bacterium or virus they tend to present parts of these invaders on their outer layer on proteins found on the cell surface named major histocompatibility complexes of class (ll) these are professional antigen-presenting cells of class two such as macrophages, dendritic cells (=langerhans cells containing large organelles called Birbeck granules) and B-cells, dendritic cells, a major antigen-presenting cells binds to the antigens present on the macrophages they then travel to the nearest lymph node in about a day to bind with specific helper T cell which has a particular receptor for the specific antigen, once it binds it matures and start producing chemicals ''cytokines'' which calls for more white blood cells to get to the site of infection and divides producing memory T cells, regulatory T cells and killer T cells.

Thanks to the following websites and youtube channels for making this possible, if you find anything difficult send me your question in either my e-mail ahmed.maxi.93@gmail.com or just in the comments below I will be awaiting your feedback and we are finally done with Immune system episodes.

References used:
http://www.endocrineweb.com/endocrinology/overview-thymus
http://www.ebioscience.com/knowledge-center/cell-type/natural-killer-t-cells/granzymes.htm
https://en.wikipedia.org/wiki/Langerhans_cell
https://en.wikipedia.org/wiki/Phagocyte#/media/File:Dendritic_cell.JPG
https://www.youtube.com/channel/UCX6b17PVsYBQ0ip5gyeme-Q
https://www.youtube.com/channel/UCsXVk37bltHxD1rDPwtNM8Q

Dendritic cell under m

Diagram showing the binding of helper T cell with dendritic cell

This video explains what is mentioned the above in a very simple way just in case you find something difficult to understand.

Overview of immune system Part 3

noreply@blogger.com (Ahmed Ashraf) — Wed, 06 Jul 2016 12:53:00 +0000

Immune system

Adaptive immune defenses

B lymphocytes & production of antibodies

B lymphocytes

Last episode we covered the innate immune defenses and how they truly use their all power and their innate property of killing and protecting you from outer invaders, we talked about phagocytes (Neutrophils & Macrophages) how they gobble them up through phagocytosis also natural killer cells and their ability to stimulate defected and cancerous cells to initiate apoptosis ''program cell death''

Today our second defenses ''adaptive immune defenses'' these defenses show up only on one condition when the innate defenses fail to take control of your body when there is an infection. In other words, when the outer invaders are overwhelming, any antigens such as bacterium, fungus, toxins, cancerous or defected cells, what characterizes your adaptive immune defenses is that they have the ability to remember the specific antigen which invaded your body also the adaptive immune defenses are more likely to be slow to progress in your body ''adaptive'' means it needs first to identify the antigen's characteristics and properties in order to initiate its attack so it is more ''specific'' than innate immune defenses also known as acquired immune defenses.

What are the defenses of the adaptive immunity?

It has two ways of defenses:

1)Humoral immunity

2)Cellular defenses ( we will discuss that in the next part)

Humoral immunity means protection of the body through something called ''Antibodies'' antibody-mediated immunity existing in extracellular fluids(ECF) '' all body fluids found outside the cell'' such as blood & lymph, antibodies(=immunoglobulins) are Y shaped little protein molecules that has the ability to block the binding sites of a particular antigen of the foreign invader, consists of heavy and light chains''

-These antibodies are produced from special immune cells named B lymphocytes, these immune cells originate in bone marrow and mature in it by learning how to recognize a foreign antigen, avoid attacking your own body's antigens ( auto-immune disease) and by dispatching more than 10,000 protein receptors (antibodies) membrane-bounded antibodies.

-Once the B lymphocytes mature they start patrolling the body's fluids such as lymph, blood and the interstitial fluids between your cells searching for any pathogens and in case it finds one which matches a particular antibody on its surface it will bind to it and they start dividing producing and differentiating into Memory cells & plasma cells ''they are special type of differentiation of B lymphocytes that preserve the threshold antibody for that specific antigen whom invaded your body'' this process is considered to be your primary immune response which will take sometime to respond and act but any further attacks that may invade your body of the same antigen will initiate the secondary immune response due to the presence of your memory cells that has the particular antibody for that antigen so it occurs much faster.

-Plasma cells are packed up with rough endoplasmic reticulum ( cell organelle studded by ribosomes molecules on its surface that's why we term it by ''rough'' functions in assembling proteins for your cells and in our case antibodies) which acts as an antibody factory, it produces the particular antibody spreading it out through your whole body fluids 2000 antibody/second for like 4 or 5 days, so we conclude that they are free-floating meaning they will be just like cells moving around till they find and bind to the foreign invader's antigen blocking them from binding to any of your cells, antibodies can fully block the sites of binding of the foreign invaders in a process called Neutralization or another way since antibody's structure have several binding sites they have the ability to bind to more than antigen of a foreign invader resulting in clumps/groups/antigen-antibody clumps in a process called Agglutination, these clumps makes it an easy target for phagocytes like macrophages to phagocytose them, this process is termed as Opsonization '' means marking or identifying the foreign invader to phagocytes, the identification is by the antibodies''

How do the phagocytes respond?
It happens that the antibodies have the ability to produce substances that attract other immune cells like phagocytes and other cells from the adaptive immune system to get to the site of infection where these bad guys are blocked to bind anything.

All that we have been discussing can be called ''Active humoral immunity'' as a definition it is when B lymphocytes mature and start to produce antibodies for the specific antigen invader, this is so important to your immunity since it increases your body's immune system efficiency and strength, the more specific antibodies for specific foreign antigens you have, the more immune you are.

Vaccination
-This is more likely to be active humoral immunity but it happens artificially without the body's own cells, a vaccine is usually a sample of the specific pathogen extremely weakened or has lost the ability to reproduce or it can't invade cells anymore which are then injected to your body, this will initiate your body's immune response to eliminate the pathogen quickly and save a copy of its characteristics & properties .e.g. the needed antibody for that specific antigen,

-Cell culture adaptation, they allow the virus to reproduce in a weak medium meaning, not human cells.e.g. they inject the virus in chicken embryos in a petri dish making the virus adapt to this type of infection (chicken embryo cells) they are then adapted to infect chicken cells since viruses reproduce a lot they then take some of the reproduced viruses and inject them into human, the virus isn't acquainted or having enough strength to reproduce and invade human cells allowing the activation of immune response to identify and get rid of the invaders while saving some other cells for any further comebacks.

Passive humoral immunity
From its name we can conclude that it is not obtained from the body's own cells, for example, babies, while they are in their development stages in their mother's womb, receives ready-made antibodies from the mother's placenta '' placenta is a sac-like organ develops from the mother's uterine wall which connects the baby to the mother through the umbilical cord, it is where the exchange of nutrients, oxygen, carbon dioxide and wastes occurs between the mother and the baby'', later on from breast milk.Unfortunately, passive humoral immunity is a temporary immunity which means the baby's own immune system won't remember any antigen it has cured of it before if it gets infected again.

Passive humoral immunity can be also obtained artificially which is usually done when the person is infected with a very serious disease which has not yet cured but some others somehow survived by receiving exogenous ( means developing or originating from outside of the organism) proteins '' antibodies'' from the plasma of other persons.

No matter what happens, somehow pathogens will find a way to get into your cells and start reproducing, this is what we are going to discuss in the next part of our overview of the immune system!

Production of antibodies

The antibodies also known as immunoglobulins are small Y shaped protein molecules that are membrane-bounded to B lymphocytes and produced from special derivatives of B lymphocytes known as plasma cells to bind to the receptors (antigens) of foreign invaders and they mainly consists of heavy & light chains connected to each other by a disulphide bridge, on the edges of these two chains there can be found the variable regions of the antibody, it is what makes each antibody different than the others while the rest are constant regions.

-Antibodies has various forms/types, the isotypes of antibodies are:
1)IgM 3)IgA
2)IgD 4)IgE
5)IgG
First of all, a progenitor B cell which is a biological cell more likely to be a stem cell differentiates to B cell which has the DNA containing genes responsible for the production of these antibodies which then later produces and put them onto its membranes making it bound to it, B cells when they are later differentiated into plasma cells which produce one specific antibody.

How heavy chains forms?

-The germline DNA(=constitutional DNA, is the source of DNA for all other cells in the body) with its long strand carrying various genes on it, the first is the ''V'' region which stands for variable, this region from its name we can say it is changeable, then the ''D'' region stands for diversity, making it the remarkable region which specializes antibodies meaning that they have variation, after that the ''J'' region stands for joining, which later on join the chains with each other, last regions are M, D, G, E & A and they are the constant regions of the antibody's structure.

The V, D & J region mainly consists of 40, 25 & 6 parts respectively, pretty much, right? That's what makes the very long number of a variety of antibodies and the big amount of them which can be produced.

The mechanism of how the heavy chains forms start by the following:

One part of each D & J region are chosen making a part of D connected to J region labeling them as DJ recombination while the V region & the constant regions connected together with the DJ recombination, after that one part of the V region leaves its friends and connect with the DJ recombination forming VDJ recombination yet the constant regions still connected to the VDJ recombination labeling this as Recombined DNA, due to the many parts present of these genes we can create many antibodies, after that the whole strand of DNA gets transcribed into mRNA strand now to the important stage which is what constant regions are made up of, the constant regions gets spliced away leaving only one of them in our example let's say it is the ''A'' region so our new piece is a VDJ regions connected with an A region naming it spliced mRNA, later on, this spliced mRNA will be translated into the proteins forming what we know as ''Antibody'' Y-shaped protein structure, the same thing happens to the formation of light chains except that there isn't a D region in its structure just directly V connected to J region.

*****

References used:

http://www.cancer.gov/publications/dictionaries/cancer-terms?cdrid=561402

http://medical-dictionary.thefreedictionary.com/opsonization

http://www.healthline.com/health/placenta-previa#Overview1

https://meducation.net/

https://www.youtube.com/channel/UCX6b17PVsYBQ0ip5gyeme-Q

Antibody's isotypes

Opsonization simple explanation

Antibody structure

Diagram showing various movements of antibodies blocking the sites of binding

Overview of Immune system Part 2

noreply@blogger.com (Ahmed Ashraf) — Fri, 01 Jul 2016 22:30:00 +0000

Immune system

Innate immune defenses

The immune system isn't like the other systems in their description. In other words, the immune system is not a full/specific organ like the other systems for example when we recall the digestive system we know we are talking about the stomach, small intestines, esophagus and so on, when we say the respiratory system we know we are talking about the lungs, alveoli sacs and etc..

The immune system is the lymph nodes, vessels, tracts & trunks, also lymphocytes and bone marrow, the immune system's job is a prerequisite in order to live, the immune system helps our body keep foreign invaders outside of our bodies such as bacteria, virus, and fungi that are waiting for any chance to use you and your body's resources to divide, so our body needs to develop special soldiers in order to avoid these bad guys, for example, our first line of defense like our external barricades is our skin, the skin is made of three layers 1)epidermis *the outermost layer* 2) dermis *the inner layer* 3) Hypodermis *the deeper layer*

1)Epidermis, several layers of epithelial cells, Stratum(corneum, lucidum, granulosm& germinativum) at the surface of this layer where the exterior cells exists are dead keratinocytes cells exists which makes up the substance of skin called Keratin, at the base of its inner layer, there are pigment cells which secrete granules responsible for the color of the skin through cells called melanocytes, the darker is your skin the more active melanin you have and vice versa.

2)Dermis, lies beneath the epidermis, consisting of connective tissues, also is crucial since it contains blood capillaries, nerve endings, lymphatics, sweat glands, fat glands, fatty cells and hair follicles, the sweat gland is one of the various points we will talk about as something related to our immune system, these sweat glands through coiled tubes that reaches the skin surface through a pore secretes sweat which mainly consists of NaCl + water, some bacteria cannot bear the acidity of such secretions our skin releases, therefore our skin has sort type of immunity to our body so we categorize it in our innate immune defenses, also the presences of some peptides called defensins
( antimicrobial polypeptides, they invade microbes )that also provides an immunity function by attacking any bacteria or fungi by binding to their membrane and increases their membrane permeability.

The presence of mucous membranes in our body that covers all the tracts that lead to the outside world such as digestive, respiratory, urinary & reproductive systems also have an immune function, mucous mainly composed of Mucin( mucin is a family of large heavily glycosylated proteins, ''glycosylation'' as a definition means the reaction in which a carbohydrate molecules ( glycosyl donor) is attached to any functional group of another molecule ( glycosyl acceptor) it is more likely a type of covalent bonding, these molecules or membranes tends to protect you from the outside world.

For example, your nasal passages containing mucous protect you from any harmful foreign invaders (airborne vectors) that you may inhale frankly as well as the presence of cilia which work on kicking out any tiny objects such as dust.

The saliva which your salivary glands secrete mucin, salts, and lysozymes among other things help protect you from anything you may take in while eating or through a mouth breath, lysozymes also known as bacteria-fighting enzymes destroys the bacteria's cell wall.

Your lacrimal eye fluid(tears) also has an immune function, it consists of water, electrolytes such as sodium & potassium, proteins such as lysozymes, immunoglobulins ( antibodies), mucin, defensins, and lipids among other things.

Your stomach which is a main digestive organ, any type of vector that somehow made it to your stomach can be eliminated due to the presence of acids secreted by the stomach in order to digest food such as HCl, pepsin, and enzymes secreted by the pancreas that tends to break down lipids, carbohydrates and proteins also tend to help in immunity.

In case any successful vector such as Staphylococcus bacteria( gram +ve bacteria) made it to through any cut you have made accidentally while peeling an orange, this induces your internal innate immune defenses where your body tends to activate a sort of weapons that work against these foreign objects such as fever, chemical signals, and inflammation,

What happens in the case of an infection?

It is a beautiful day until you accidentally cut your skin, nearby bacteria seize the opportunity and enters through your wound starting to divide, your body's first line of defense that arrive to the scene are phagocytes such as neutrophils which are the most abundant type of your innate immune cells they range in percentage of 40 to 70% they mainly destroy the bacteria and any toxins secreted by them their nucleus has two to six lobes also they tend to commit a suicide right after destroying any foreign invaders.

Another type of phagocytes which are bigger are Macrophages meaning big eaters, they have two types, mobile and fixed, the fixed ones such as those found in the liver where they are fixed on the liver cells tissues and others are mobile which has the ability to move around, they kill bacteria by engulfing them through cytoplasmic extensions through a process called phagocytosis, where the bacteria is eaten and digested due to the presence of various and more lysosomes ( lysosome is a cell organelle found in eukaryotic cells functions in digestion and waste removal so it has enzymes) these lysosomes tends to surround the bacteria and releases its enzymes, what characterizes the macrophages unlike the neutrophils they can devour many bacteria, fungi or viruses up to 100, macrophages are derived from immune phagocytic immune cells known as monocytes comprises about 3 to 8%, these cells that has left the bloodstream.

Natural killer cells, these cells aren't phagocytic, these immune cells patrol all your body cells looking up for any infected cells that has been infected by any sort of a vector, through cell signaling by sending messenger proteins which tends to activates a process known as apoptosis '' program cell death'' induces the cell to kill itself, the way the natural killer cells identify the infected or cancerous cells is that each normal cell has a special antigen called MHC1 '' Major histocompatibility complex'' also known as human leukocyte antigen ( are group of genes that expresses proteins found on the surface of cells that help the immune cells to identify any foreign invaders) but when any normal healthy cell gets infected they lose this antigen.

So back to the cut you had when you were peeling the orange, bacteria nearby embrace the opportunity and gets through, your body innately tends to protect you from any loss or any breach from foreign invaders into your body, so your damaged skin cells that have been affected by the cut releases chemicals known as chemokines ( small protein molecules, chemo>>chemical, kines>>kinetic*movable*) which tends to inform your body that something has gone wrong then this launches inflammatory response through chemicals, redness, swelling, heat, and pain for example in your dermis skin layer exactly in the connective tissue of this layer has specialized cells called mast cells ( are cells filled with basophils granules that releases histamine molecules & other substances during allergic reactions and inflammatory responses) mast cells basically fight worms, communicate with other cells, activate cells and causes inflammation as well among other things, histamine molecules one of the main factors of causing the inflammatory response, it goes to the capillaries feeding the skin cells with oxygen & nutrients deeper into the endothelial cells layer stimulating them to widen & separate between each other to make the capillaries larger leading to what we call vasodilation which makes you feel with enlargement or swelling, this is helpful and are actual signs of healing since it helps increase the blood flow to the damaged tissue, platelets start to clot the wound in order to prevent more blood loss, fibroblasts found in the connective tissues secrete collagen( main structural protein found in the connective tissues of animals) towards the cut to take the shape of the original worn out tissue.
Since the capillaries are vasodilated and capillaries contain blood which in our case has lymphocytes and white blood cells that pass by, they will squeeze through the separated/widened capillaries moving towards the site of infection through a process called leukocytosis it is also a sign of inflammatory response where the number of white blood cells increases in number during an infection but when the foreign invaders are overwhelming the macrophages and neutrophils releases fever-inducing substances called pyrogen ( low molecular weight protein, endogenous since it is produced from the leucocytes) in response to the exogenous pyrogen released from the bacteria (foreign invaders) released into the blood circulation which stimulates the hypothalamus.
The hypothalamus is a section of the brain responsible for the production of many essential hormones that control different organs and cells, in our case the hypothalamus among other things is responsible for temperature regulation, thirst, and hunger, so when the pyrogen chemicals are released they stimulate the hypothalamus to increase the body temperature resulting in a higher metabolism of your cells making them consume more oxygen& nutrients leading to a faster healing, also this induces the liver and spleen to hold their iron and zinc in order to prevent the contribution of these materials to the growth of these foreign invaders that's why the person infected with any bacteria or virus tends to breathe heavily, lose appetite and feels sleepy among other things.

Thanks to the following websites and youtube channels for making this overview possible and I really hope you get educated and I am hoping you give me your feedback in the comments section, Thanks a lot.
References used:
http://www.healthline.com/human-body-maps/hypothalamus
http://medical-dictionary.thefreedictionary.com/pyrogen
https://www.britannica.com/science/major-histocompatibility-complex
https://www.boundless.com/physiology/textbooks/boundless-anatomy-and-physiology-textbook/integumentary-system-5/accessory-structures-of-the-skin-65/sweat-sudoriferous-glands-397-4497/
http://www.nature.com/eye/journal/v17/n8/fig_tab/6700566t1.html#figure-title
http://www.medicinenet.com/script/main/art.asp?articlekey=26300
https://www.youtube.com/channel/UC4a-Gbdw7vOaccHmFo40b9g (Khan Academy)
https://www.youtube.com/channel/UCX6b17PVsYBQ0ip5gyeme-Q (CrashCourse)

Stay tuned for the next part, we will talk about some adaptive immune defenses!!

Diagram showing the existence percentage of some white blood cells in the blood

Capillary tube contents after centrifuge, discussing the presence of platelets that clots the damaged tissues, lymphocytes and white blood cells

Capillary beds and the exchange of gases and nutrients to the damaged tissues

Overview of the lymphatic and immune system Part1

noreply@blogger.com (Ahmed Ashraf) — Tue, 21 Jun 2016 02:44:00 +0000

LYMPHATIC SYSTEM

Lymphatic system: It is a network of vessels, organs and tissues containing lymph which is a fluid containing infection-fighting white blood cells that spreads throughout the body.

Also a part of circulatory system and plays a vital role to our immune system

Lymph is the interstitial fluid that gets absorbed when forced out of the capillary tubes.

-One function of the lymphatic system is that it maintains our body's homeostasis.

Homeostasis means balance, a way or process your body does by controlling the concentrations of substances in solution, temperature, etc.. in order to remain everything near constant level, the plasma membrane is so related to homeostasis so check out the last video below for more understanding.

Any failure to perform homeostasis may lead to life threatening consequences such as swelling ankles, lungs can be filled by fluids, the failure to control concentrations can decrease the blood pressure and volume.

Lymphatic system structure:

1-Lymph, a watery(liquid) solution which is most likely to be plasma and NOT blood; because red blood cells are big enough that they cannot squeeze out of your capillaries

Mainly consists of blood plasma which is forced out of your capillaries where the leakage helps the exchange of nutrients and gases between the blood and capillaries and the cells.

2-Lymph nodes, network of lymphatic vessels reabsorb the blood fluid (lymph) which transport them to lymph nodes which are found at certain points throughout the body, they are more likely to be your checkpoints, they help in monitoring/cleaning/eliminating any microbes or such foreign bodies present in your lymph.

3-Lymphatic organs: a-Spleen( major lymphatic organ) found in a suitable and safe place behind the stomach and just in the front of the left lobe of your liver, spleen has various functions such as getting rid off of dead red blood cells, oxygen-rich blood reservoir and cleans the blood off foreign invaders

b-Thymus gland, a gland that exists in your neck behind the sternum in an appropiate place between your lungs, also provide a vital immunity role to your body by secreting thymosin hormone which stimulates the maturation of disease-fighting lymphocytes called T-lymphocytes

c-Adenoids

d-Tonsils

Both the spleen & thymus provides a safe place for immune cells such as T and B cells, natural killer cells, dendritic cells and R.B.Cs.

Starting from the capillaries......,

The capillaries are tiny, microscopic vessels which connects the arterioles with the venules.

Carries blood from your arterioles and feed blood into venules, their walls which are very thing consists of one row of thing epithelial cells with tiny pores between them, the wall of the capillary is about 0.001 micron thick which facilitates a quick exchange of substances between the blood and the tissue cells.

Capillaries are spread in the spaces present all over the body tissues as a wide irrigation system.

The exchange of nutrients and gases is due to osmotic pressure, it is the diffusion of solutions/substances through a semi-permeable membrane, it increases by the increase in concentration of solutes in solutions.

-About 3 liters per day of the fluids which is about more than half of your total blood volume that passes through the blood capillaries are picked up by the lymphatic capillaries that exists through the spaces present in the capillary vessels. Their walls consist of endothelial cells with valves that opens only in one direction, the presence of smooth muscles in the inner lining roles in moving the lymph as well as the skeletal muscles which when squeezing (contracting) increases the pressure on the lymphatic vessels and therefore, the lymph moves forward.

These walls are forced to be opened when the concentration of solutes on the outside is more than that on the inside of the lymphatic vessel. Once filled, it is then taken to various nodes and are eventually drained into two big ducts.

-The right lymphatic duct takes lymph from the upper right area of the Torso, including the right upper arm and right side of the head & thorax feeding all into the Internal Jugular Vein ( a major blood vessel that drains blood from important body organs and parts such as the brain, face and neck, they functions in carrying oxygen-depleted (less) blood from the brain, face and neck and transport it to the heart through the superior vena cava).

-The larger thoracic duct takes lymph from the rest if your body sending them into the subclavian vein.

Lymphatic vessels works under low pressure, containing valve that prevents any back flows as well as the presence of smooth muscles that help in movement and support.

Any decent exercises or movements are good enough to help keep up your lymphatic vessels.

Ultimately, the lymphatic system functions in taking extra fluids and cleans it from any microbes.

Now back to the vital role of the lymphatic system to our immune system, throughout our lives our skin which is considered to be the largest organ is surrounded by many bacteria that standing for any chance to infect your body starting from a small cut in your skin.

For example, staphylococcus bacteria (gram +ve bacteria) sneaks through your loose areolar connective tissue ( a multi-functional tissue that serves structural, adhesive, and immunological functions consists of collagenous fibers and elastic fibers )

Recall lymph nodes....?

Since they contains the checkpoints in other words, the protection against foreign bodies that wants to breach our body, it is also the place for lymphocytes exists (T & B) and where they mature in the loose reticular connective tissue that makes up a large part of the nodes and most of your other lymphoid organs.
-Lymph enters the lymph nodes through a vessel called Afferent vessel and exits through Efferent vessel

Mucosa associated lymphoid tissues

a.k.a MALTs are also tissues that functions like our lymph nodes such as tonsils (two small masses of lymphoid tissues in the throat), Mucosa? because they are present in the mucous membrane outside the lymphatic vessels, the tonsils inspect everything that you eat, another example is peyer's patches found in the distal portion of small intestines ( consists of a group of lymph nodes) also appendix ( which happens to have lymphatic nodes & vessels)

Figures

Diagram of a lymph node showing its structure

Picture showing the structure of a lymphatic vessel

Diagram of the lymphatic vessel showing its structure and its histology

Loose reticular connective tissue diagram

Diagram showing lymph capillaries in between blood capillaries

Loose areolar connective tissue

I hope you guys enjoyed the topic today, the following videos will help you revise and understand with extra information about the lymphatic system, I don't own any of the following videos also stay tuned for more biology stuff and the next parts of this overview =) WE LIVE WE LEARN

Thanks to Tammy Moore, here is her channel https://www.youtube.com/user/armoorefam

Thanks to CrashCourse, channel's link: https://www.youtube.com/user/crashcourse

Thanks to Jenny Klemme, here is her channel: https://www.youtube.com/channel/UC1WLVcjqO44TPUnV2zvPrcQ

Thanks to Amoeba sisters, link to their channel: https://www.youtube.com/channel/UCb2GCoLSBXjmI_Qj1vk-44g

Next part will be more into the immune system deeper into it, we will discuss immune cells their functions also we will have an example to help in understanding what happens when the body is infected, it will be about bacterial infection.

What you want to know about ''Homeostasis'' is here,

A quick peek about the various body tissues we got

Measles - how it spreads, brief notes on how it infect us and it's cure

noreply@blogger.com (Ahmed Ashraf) — Fri, 13 May 2016 23:02:00 +0000

MEASLES

Structure and taxonomy
Measles is a single stranded enveloped RNA virus surrounded by a protein coat, Genus: Morbilivirus, Family:Paramyxoviridae, it's host has always known to be human host cells and it's common infection in children also a very infectious disease. (See FIG.1)

Notice: you need to be aware of some of the Immune system's cells in order to understand some of the next questions.

It's TRANSMISSION

Measles is said to be one of the most infectious diseases( an airborne viral disease), it can be transmitted through several ways such as sneezing, coughing, measles can live for a couple of hours in the air which therefore can be transmitted through breathing and touching things contaminated with the virus.

DIAGNOSIS

Diagnosing measles virus can be performed through several ways such as: blood test, urine test or throat swab (see fig.2 to know what throat swab is)

Whom are most likely to be infected with measles?
-The elderly, very young individuals (can lead to their death), pregnant women, immunosuppressed individuals and those who are malnourished.

Mechanism of prevailing in our body.

Measles can enter our body through nose, mouth or eyes, measles is especially good at infecting our body's first line of defense within our lungs ( the beginning of infection) cells called Macrophages these cells exists all over our body and usually known as powerful eaters where they have the ability to devour foreign bodies up to 100 of them, it uses the macrophages' cell machinery and reproduce itself through the cells resources until the cell is full of viruses, they leave it and begins the cycle all over again. Fortunately, our immune system has some powerful immune cells called ''Natural killer cells'' these cells main job is to patrol the entire body and check other cells for infection, in case they find an infected cell they order it to commit a suicide through messenger proteins by a process called '' cell signaling''.

Measles symptoms usually are to be noticed after like 10 to 12 days ( Incubation period), after a period of time, macrophages alerts the BRAIN of the immune system ''Dendritic cells'', the dendritic cell's job is to collect samples of the intruders, travel to the lymph nodes and then activate the heavy weapons that erases the virus. Unfortunately, the measles virus uses such a mastermind or a dreadful tactic just like what is said in the video down below, it infects the dendritic cells and travel to lymph nodes and starts infecting your immune vault, the soldiers of your body "B & T lymphocytes), at last the lymph system spreads the virus everywhere infecting lots of organs and damaging many cells.

Now the symptoms of measles virus starts showing up, it infects various organs such as the spleen, intestines, liver, the lung, some cases infects the brain, etc..

Leading to a very high fever, headache, sickness, bronchitis, rash ( shows up at the beginning of infection sometimes) and much more..

The lymph system is weakened at the current moment making a chance for bacteria and other viruses that would take a chance of this and develop into secondary infections that can cause Pneumonia, at this stage our bodies are completely in an exhaustion giving an advantage of the virus to take over YET our body is far and away from giving up which is kind of a tremendous and fascinating thing to be proud of being a persistent and it fights back furiously, some of our dendritic cells survive long enough, they then activate our heavy weapons (T and B lymphocytes) B lymphocytes which then differentiate into ''Plasma cells'' that produces billions of antibodies a.k.a Immunoglobulins '' Y shaped tiny protein molecules that mark infected cells for destruction or clump the viruses, they consist of heavy chains and light chains'' T lymphocytes spread all over the body and kills infected cells.

About time now for our immune system to take a consideration of such disease by ordering some immune cells to save the specific type of antibody this virus needed to be obstructed and recognize the virus in case of it made a comeback.

IT'S CURE.

The best way to prevent measles is vaccination which became normally found in childhood vaccinations programmes, although some people cannot get vaccinations such as pregnant women, people who has immunosuppressions, chemotherapy patients or those who are diagnosed HIV-positive.

They does that by doing a process called ''Cell culture adaptation'' which allows the virus to reproduce in a medium that isn't human cells, this is done by injecting the virus in chicken embryos in a petri dish making the virus adapt to this type of infection ( chicken ) they are adapted to infect chicken cells since measles reproduces a lot they inject the individual with this virus which is weak comparable to human cells reproduces about 20 times this reduces the symptoms but activate immune response.

We can still are able to help find other ways to stop the disease from spreading for those people just like how we could make it with ''smallpox''

Thanks to Kurzgesagt, SciShow and Let's learn about bugs for making this easy to understand.

I don't own any of the following videos, they are only brought to help you understand brief notes about measles, so helpful and useful videos and I hope you guys find this informative.

Here are links to the YouTube channels I got these videos from:

https://www.youtube.com/channel/UCZYTClx2T1of7BRZ86-8fow

https://www.youtube.com/channel/UCsXVk37bltHxD1rDPwtNM8Q

https://www.youtube.com/channel/UCSktYEB73WQ3mOOLyBfRsPA

Also thanks to http://www.who.int/immunization/diseases/measles/en/

Keep tunned for more biology-related topics!

FIG.1

FIG.2

Pancreas- brief notes

noreply@blogger.com (Ahmed Ashraf) — Fri, 06 May 2016 22:57:00 +0000

The Pancreas

Pancreas is considered to be a mixed gland. this organ controls our body's sugar level and produces a special juice called pancreatic juice that literally releases the nutrients present in any meal you have eaten so it has a role in our Metabolism, the pancreas is situated behind our stomach see Fig.1 which means that one of its main functions is to assist in breaking down food through a mixture made of water, sodium bicarbonate and digestive enzymes.

Sodium bicarbonate's role is to neutralizes the stomach's acidity so as to let the digestive enzymes perform their functions, enzymes such as Lipase, Protease, and Amylase. (exocrine function) these digestive enzymes are secreted from cells called Acinar cells see Fig.2

Lipase breaks down the fatty substances

Protease help in splitting up proteins

Amylase divides carbohydrates into energy-rich sugars

So these past three enzymes have a great role in our metabolism, another function of the pancreas which is considered to be crucial is controlling the amount of sugar in the human's blood through two hormones:

Insulin and glucagon which are produced from special small glandular cells in the pancreas called the Islets of Langerhans (endocrine function) see Fig.3 the islets of langerhans has two types of cells (alpha & beta cells) see Fig.4

The alpha cells are usually small in number and secretes glucagon hormone, this hormone is secreted only when the blood sugar level is falling down or too low, by telling the cells and livers to release sugar in the bloodstream, converting the stored glycogen for example in the liver to glucose.

The beta cells represents the majority of cells and secretes a hormone called insulin which antagonizes the action of glucagon. Mainly it makes the excess sugar moves back to the cells, it stimulates the oxidation and utilization of glucose by the cells as it is important for transport of all monosaccharides (except fructose) across the cell membrane also stimulates the conversion of glucose to glycogen ( to be stored in the liver or muscles) or to lipids.

We can say that the balance between insulin and glucagon is what keeps our body's health maintained but any failure in either the secretion of insulin or glucagon can lead to a condition called Diabetes Mellitus, the increase in glucose level in the blood is associated with abnormal appearance, excretion of glucose in urine with the excretion of large volume of water which explains the symptoms of continuous thirst sensation and excessive micturition, blood vessels becomes hardened, heart attacks, kidney failure and strokes.

Also from what we learn from this video is that people who have diabetes their body tends to have high glucagon level which increases the sugar level making it worse.

The pancreas is more like an instructor that guides our body to maintain a good health.

Like and share it please incase you find it informative to let everyone knows about this important topic.

Also follow our facebook page for more biology-related topics! https://www.facebook.com/biologyclub17/

Thanks to #TedEd for developing this video which is full important and helpful notes

Fig.1

Fig.2

Fig.3

Fig.4

Alzheimer's disease

noreply@blogger.com (Ahmed Ashraf) — Wed, 04 May 2016 22:28:00 +0000

Alzheimer's disease

Well most of us have a very narrow knowledge related to this magnificent disease which is Alzheimer's disease, In my point of view and my anticipations says that most of those whom I know knows only that Alzheimer means memory loss, well yes it is but that's not only its symptom, Alzheimer's disease is kind of a successful disease (a brain disorder); due to a couple of reasons but firstly, it has been discovered in 1906 by Dr. Alois Alzheimer a German psychiatrist, and guess what people 110 years since its discovery yet none ever could find a cure to eliminate Alzheimer's disease, the only treatment reached so far are only made to slow its progression.
To be honest in front of you all, I am really afraid since the day I have read about this disease, it scares me and I felt so sorry for those who has it and those who died of it. God be with you.
Anyway, Alzheimer's disease not only loosens its patient his memory but also it causes several damage to him, Symptoms starts by: 1)Short memory loss
2)Lack of the ability to perform logical thoughts
3)Erratic mood changes (through infecting the part that controls emotions in the brain)
4)Paranoia and hallucinations
5)Long term memory loss
Eventually 6)It takes over the control centers leading to a fail in pumping blood as well as breathing resulting to death.
How Alzheimer's disease progress ?
Through an autopsy( an examination that is done to the person after his death (corpse) to evaluate and identify the reasons of the death through a highly surgical operation, they found out in the brain structure the presense of misfolded proteins ( meaning they are not in their suitable or right place) Protein folding is a process by which the protein molecules tend to attach together in order to arrange its functional shape, the misfolded proteins are called plaques (are small differentiated areas on the body surface or on organs such as the brain in our case) plaques are formed when an enzyme slices the fatty membrane surrounding the nerve cells (mylein sheath) resulting in beta-amyloid proteins ( these proteins' role is neural growth and repair any damage ) but any corrupted form later in life leads to the lose of memory among other things, they then group together due to their sticky status which form what we mentioned ''plaques'' their grouping blocks the cell signaling such as any messenger proteins and pulses and therefore the communcation between cells, these defected cells due to the formation of these plaques and tangles lead to the triggering of immune reactions causing the destruction of the disabled nerve cells and also found neurofibrillary tangles neurofibrillary (nerve fibers) tangles ( grouping) so neurofibrillary tangles are the grouping of nerve fibers in a confusing way making a complex structure, they are built from a protein known as tau ( tau protein is a protein that tends to stabilize the microtubules found in the neurons of the central nervous system which is more likely to be a network that receives oxygen, food molecules and nutrients to the brain's nerve cells.

In Alzheimer's disease these proteins becomes twisted strands meaning the passage of nutrients to the brain's nerve cells are obstructed which leads to the death of these cells eventually.

Follow my page on facebook to keep yourself posted! https://www.facebook.com/biologyclub17/

Just in case everyone since I have noticed the video is not working properly, here is a direct link to the video on youtube I am so sorry: https://www.youtube.com/watch?v=yJXTXN4xrI8

Figure showing how Alzheimer's disease on the brain
Thanks to Alzheimer's association for developing this picture showing us the result of the destructive pairing of plaques and tangles on some brain parts